Rinse‐free hand wash for reducing absenteeism among preschool and school children

Abstract

Background

Illness‐related absenteeism is an important problem among preschool and school children for low‐, middle‐ and high‐ income countries. Appropriate hand hygiene is one commonly investigated and implemented strategy to reduce the spread of illness and subsequently the number of days spent absent. Most hand hygiene strategies involve washing hands with soap and water, however this is associated with a number of factors that act as a barrier to its use, such as requiring running water, and the need to dry hands after cleaning. An alternative method involves washing hands using rinse‐free hand wash. This technique has a number of benefits over traditional hand hygiene strategies and may prove to be beneficial in reducing illness‐related absenteeism in preschool and school children.

Objectives

1. To assess the effectiveness of rinse‐free hand washing for reducing absenteeism due to illness in preschool and school children compared to no hand washing, conventional hand washing with soap and water or other hand hygiene strategies.

2. To determine which rinse‐free hand washing products are the most effective (if head‐to‐head comparisons exist), and what effect additional strategies in combination with rinse‐free hand washing have on the outcomes of interest.

Search methods

In February 2020 we searched CENTRAL, MEDLINE, Embase, CINAHL, 12 other databases and three clinical trial registries. We also reviewed the reference lists of included studies and made direct contact with lead authors of studies to collect additional information as required. No date or language restrictions were applied.

Selection criteria

Randomized controlled trials (RCTs), irrespective of publication status, comparing rinse‐free hand wash in any form (hand rub, hand sanitizer, gel, foam etc.) with conventional hand washing using soap and water, other hand hygiene programs (such as education alone), or no intervention. The population of interest was children aged between two and 18 years attending preschool (childcare, day care, kindergarten, etc.) or school (primary, secondary, elementary, etc.). Primary outcomes included child or student absenteeism for any reason, absenteeism due to any illness and adverse skin reactions.

Data collection and analysis

Following standard Cochrane methods, two review authors (out of ZM, CT, CL, CS, TB), independently selected studies for inclusion, assessed risk of bias and extracted relevant data. Absences were extracted as the number of student days absent out of total days. This was sometimes reported with the raw numbers and other times as an incidence rate ratio (IRR), which we also extracted. For adverse event data, we calculated effect sizes as risk ratios (RRs) and present these with 95% confidence intervals (CIs). We used standard methodological procedures expected by Cochrane for data analysis and followed the GRADE approach to establish certainty in the findings.

Main results

This review includes 19 studies with 30,747 participants. Most studies were conducted in the USA (eight studies), two were conducted in Spain, and one each in China, Colombia, Finland, France, Kenya, Bangladesh, New Zealand, Sweden, and Thailand. Six studies were conducted in preschools or day‐care centres (children aged from birth to < five years), with the remaining 13 conducted in elementary or primary schools (children aged five to 14 years).

The included studies were judged to be at high risk of bias in several domains, most‐notably across the domains of performance and detection bias due to the difficulty to blind those delivering the intervention or those assessing the outcome. Additionally, every outcome of interest was graded as low or very low certainty of evidence, primarily due to high risk of bias, as well as imprecision of the effect estimates and inconsistency between pooled data. For the outcome of absenteeism for any reason, the pooled estimate for rinse‐free hand washing was an IRR of 0.91 (95% CI 0.82 to 1.01; 2 studies; very low‐certainty evidence), which indicates there may be little to no difference between groups. For absenteeism for any illness, the pooled IRR was 0.82 (95% CI 0.69 to 0.97; 6 studies; very low‐certainty evidence), which indicates that rinse‐free hand washing may reduce absenteeism (13 days absent per 1000) compared to those in the 'no rinse‐free' group (16 days absent per 1000). For the outcome of absenteeism for acute respiratory illness, the pooled IRR was 0.79 (95% CI 0.68 to 0.92; 6 studies; very low‐certainty evidence), which indicates that rinse‐free hand washing may reduce absenteeism (33 days absent per 1000) compared to those in the 'no rinse‐free' group (42 days absent per 1000). When evaluating absenteeism for acute gastrointestinal illness, the pooled estimate found an IRR of 0.79 (95% CI 0.73 to 0.85; 4 studies; low‐certainty evidence), which indicates rinse‐free hand washing may reduce absenteeism (six days absent per 1000) compared to those in the 'no rinse‐free' group (eight days absent per 1000). There may be little to no difference between rinse‐free hand washing and 'no rinse‐free' group regarding adverse skin reactions with a RR of 1.03 (95% CI 0.8 to 1.32; 3 studies, 4365 participants; very low‐certainty evidence). Broadly, compliance with the intervention appeared to range from moderate to high compliance (9 studies, 10,749 participants; very‐low certainty evidence); narrativley, no authors reported substantial issues with compliance. Overall, most studies that included data on perception reported that teachers and students perceived rinse‐free hand wash positively and were willing to continue its use (3 studies, 1229 participants; very‐low certainty evidence).

Authors' conclusions

The findings of this review may have identified a small yet potentially beneficial effect of rinse‐free hand washing regimes on illness‐related absenteeism. However, the certainty of the evidence that contributed to this conclusion was low or very low according to the GRADE approach and is therefore uncertain. Further research is required at all levels of schooling to evaluate rinse‐free hand washing regimens in order to provide more conclusive, higher‐certainty evidence regarding its impact. When considering the use of a rinse‐free hand washing program in a local setting, there needs to be consideration of the current rates of illness‐related absenteeism and whether the small beneficial effects seen here will translate into a meaningful reduction across their settings.

Plain language summary

Rinse‐free hand wash for reducing absenteeism among preschool and school children

Background

Absenteeism from schooling is costly to parents, schools and governments and sustained absence is detrimental to student learning. Illness‐related absenteeism is a significant contributor to absenteeism from school, but can also result in parents missing work due to catching the illness themselves or having to stay home to care for their children. There are several strategies currently used to reduce illness‐related absenteeism, a common method is the implementation of appropriate hand hygiene practices. However, hand hygiene using soap and water is not always practical, and alternatives may prove to be more effective in reducing the overall rate of illness‐related absenteeism. One such alternative is the use of rinse‐free hand wash.

Review question

This review was designed to investigate if the use of rinse‐free hand wash can reduce the number of days spent absent from school in preschool and school children compared to no rinse‐free hand wash usage.

Study characteristics

The searches returned 19 relevant studies with a total of 30,747 participants. Eight studies were conducted in the USA, two were conducted in Spain, and one each in China, Colombia, Finland, France, Kenya, Bangladesh, New Zealand, Sweden, and Thailand. Six studies were conducted in preschools or day‐care centres (children aged from birth to < five years), with the remaining 13 conducted in elementary or primary schools (children aged five to14 years). These studies were quite varied in the composition and application of the rinse‐free hand washing program. Only two studies included information on the primary outcome (absenteeism due to any reason), whilst for absenteeism for any illness there were six studies that provided information. The evidence presented is up to date to February 2020.

Key results

The application of, and adherence to a rinse‐free hand wash, hand hygiene program may be associated with small, but potentially beneficial effects in reducing the number of days students were absent from school due to illness compared to no rinse‐free hand wash, hygiene program. However rinse‐free hand washing may be no different to controls at reducing absenteeism for any reason. There may also be no difference in the number of skin irritations between students who received the rinse‐free hand wash compared to those who used soap and water. Most students and teachers responded favorably to using rinse‐free hand wash and complied relatively well with its use.

Certainty of the evidence

The certainty of the evidence included in this review was low or very low, mainly due to the included studies using poor methods, providing imprecise data, and being very inconsistent from one another. This means that we have low and very‐low certainty, or confidence, in these results.

Summary of findings

Summary of findings for the main comparison. Rinse‐free hand wash compared to control for reducing absenteeism among preschool and school children.

Rinse‐free hand wash compared to no rinse‐free hand wash program for reducing absenteeism among preschool and school children
Patient or population: children aged from birth to 14 years old Setting: preschool/kindergarten and elementary/primary School Intervention: rinse‐free hand washing program Comparison: no rinse‐free hand washing program
Outcomes	Anticipated absolute effects* (95% CI)		Relative effect (95% CI)	№ of participants (studies)	Certainty of the evidence (GRADE)	Comments
	Risk with control	Risk with rinse‐free hand wash
Absenteeism for any reason (within the study period) Calculated as: an incident rate per child‐days possible Length of time observed: range = 5 to 6 months	Baseline risk (Priest 2014)aa		Incidence rate ratio 0.91 (0.82 to 1.01)	(2 RCTs)	⊕⊝⊝⊝ Very lowa	‐
	32 days absent per 1000	29 per 1000 (26 to 32)
Absenteeism due to any illness (within the study period) Calculated as: an incident rate per child‐days possible Length of time observed: range = 1 to 11 months	Baseline risk (Priest 2014)bb		Incidence rate ratio 0.82 (0.69 to 0.97)	(6 RCTs)	⊕⊝⊝⊝ Very lowb	‐
	16 days absent per 1000	13 per 1000 (11 to 16)
Adverse skin reactions (within the study period) Calculated as: number of events Length of time observed: range = 5 to 8 months	Study population		RR 1.03 (0.80 to 1.32)	4365 (3 RCTs)	⊕⊝⊝⊝ Very lowc	‐
	47 per 1000	49 per 1000 (38 to 62)
Absenteeism due to acute respiratory illness (within the study period) Calculated as: an incident rate per child‐days possible Length of time observed: range = 1 to 8 months	Baseline risk (Azor Martinez 2018)cc		Incidence rate ratio 0.79 (0.68 to 0.92)	(6 RCTs)	⊕⊝⊝⊝ Very lowd	‐
	42 days absent per 1000	33 per 1000 (28 to 39)
Absenteeism due to acute gastrointestinal illness (within the study period) Calculated as: an incident rate per child‐days possible Length of time observed: range = 1 to 8 months	Baseline risk (Prazuck 2010)dd		Incidence rate ratio 0.79 (0.73 to 0.85)	(4 RCTs)	⊕⊕⊝⊝ Lowe	‐
	8 days absent per 1000	6 per 1000 (6 to 7)
Compliance with the intervention or program Assessed with: different measures of compliance Length of time observed: range = 1 to 12 months	9 studies addressed compliance using diverse approaches. Broadly, compliance with the intervention appeared to range from moderate to high compliance. Narrativley, no authors reported substantial issues with compliance.			10,749 (9 RCTs)	⊕⊝⊝⊝ Very lowf	‐
Perception of the hand hygiene strategy or satisfaction with the hand hygiene strategy Assessed with: different measures of perception Length of time observed: range = 3 to 11 months	3 studies addressed perception. Of these, 2 studies, Pickering 2013 and Vessey 2007, conducted semi‐structured interviews with staff and students. No numerical data were reported by Pickering 2013; however, rinse‐free hand wash was perceived favorably by the teaching staff. Vessey 2007 reported that 100% of interviewed staff would prefer rinse‐free hand wash over soap at their school; 91% of students interviewed stated they would preferentially choose rinse‐free hand wash over soap and water to wash their hands. 1 study, Correa 2012, reported that teachers of rinse‐free hand wash‐assigned schools perceived rinse‐free hand wash positively and were willing to continue its use.			1229 (3 RCTs)	⊕⊝⊝⊝ Very Lowg	‐
*The risk in the intervention group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RCT: Randomised controlled trial.
GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty: our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect. Very low certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect.

^a Downgraded two levels due to a high risk of performance bias and detection bias, as the students, parents of students and teachers were aware of treatment assignment. Both studies are also at high risk of attrition bias. Downgraded one level due to confidence intervals ranging from a potentially important difference (0.82) to a negligible difference (1.01).
 ^b Downgraded two levels due to a high risk of selection bias, as random assignment was only confirmed in two studies. High risk of performance bias and detection bias, as students, parents of students and teachers were aware of treatment assignment in all but one study. Downgraded one level due to very high statistical heterogeneity (Chi² = 28.24, P < 0.001; I² = 82%). Minimal overlap between study confidence intervals. Downgraded one level due to wide confidence intervals ranging from a potentially important difference (0.69) to a negligible difference (0.97).
 ^c Downgraded two levels due to a high risk of performance bias and detection bias, as the students, parents of students and teachers were aware of treatment assignment in all included studies. High risk of detection bias, as only one study provided clear detail as to the blinding of the outcome assessors.Downgraded one level due to wide confidence intervals ranging from a potentially important benefit (0.8) to a potentially important harm (1.32).
 ^d Downgraded one level due to very high statistical heterogeneity (Chi² =27.45, P < 0.001; I² = 82%). Minimal overlap between study confidence intervals. Downgraded two levels due to a high risk for both performance and detection bias. In all but one study, students, parents of students and teachers were aware of treatment assignment. In addition, only one study provided clear detail as to the blinding of the outcome assessors.
 ^e Downgraded two levels due to a high risk of selection bias, as only two studies included clear details on randomization, and one study provided clear detail on allocation concealment. Also, a high risk of both performance and detection bias. In all but one study, students, parents of students and teachers were aware of treatment assignment. In addition, only one study provided clear detail as to the blinding of the outcome assessors. Downgraded one level due to very high statistical heterogeneity (Chi² = 21.48, P < 0.001; I² = 86%). Minimal overlap between study confidence intervals.
 ^f Downgraded two levels due to a high risk of both performance and detection bias. In all but one study, students, parents of students and teachers were aware of treatment assignment. In addition, one study that provided comparative outcome data for compliance reported that researchers were not present to observe every handwashing event, making results unreliable. Downgraded one level for imprecision, as measures of compliance varied significantly between studies and were often conducted on a subset of students, with no precise estimates provided.
 ^g Downgraded two levels due to a high risk of both performance and detection bias. None of the included studies blinded the students or teachers to treatment assignment. Only one study confirmed randomisation, indicating an unclear risk of selection bias for the outcome overall. Downgraded one level for imprecision, as measures of perception varied between studies and only a small subset of teachers and students were sampled, with no precise estimates provided.

^aaBaseline risk for absenteeism for any reason was calculated using the values provided in the study by Priest 2014 as 3.2% (days spent absent over child‐days possible).
 ^bbBaseline risk for absenteeism due to any illness was calculated using the values provided in the study by Priest 2014 as 1.6% (days spent absent over child‐days possible).
 ^ccBaseline risk for absenteeism due to respiratory illness was calculated using the values provided in the study by Azor Martinez 2018 as 4.2% (days spent absent over child‐days possible.
 ^ddBaseline risk for absenteeism due to gastrointestinal illness was calculated using the values provided in the study by Prazuck 2010 as 0.8% (days spent absent over child‐days possible).

Background

Description of the condition

Absenteeism due to sickness (particularly gastrointestinal or minor respiratory illness) is an important problem for schools in low‐, middle‐ and high‐income countries (Day 1993; Early 1998; Guinan 1997; Kimel 1996; Master 1997; Monsma 1992; Niffenegger 1997). The common cold alone has been shown to result in approximately 22 million days absent from school per year in the USA (Adams 1999), and young children are likely to have between six and eight colds per year, decreasing to between two and four colds per year in adults (Heikkinen 2003). Not only are children adversely affected by repeated respiratory infections, family members can also be affected due to infections transmitted by an infected child (Neuzil 2002). When a child is ill, this can result in work‐related absence due to parental illness or due to the need to remain at home to care for their child (Neuzil 2002).

Many strategies for reducing the spread of infectious diseases in children have been studied, such as hand washing (Lee 2010), education or training (Lee 2010; Roberts 2000), safe water supply (Esrey 1985; Lee 2010), environmental cleaning (Harris 2010; Lee 2010), exclusion periods (Lee 2010; Richardson 2001), and vigilance during food preparation (Lee 2010). While conventional hand washing with soap and water is an effective method of hand hygiene for the prevention of the spread of infectious diseases, it is difficult to maintain compliance with conventional hand washing, and its consistency and effectiveness among preschool (three to five‐year olds) (Niffenegger 1997) and school students is variable (Day 1993; Early 1998; Guinan 2002; Kimel 1996; Monsma 1992). There may also be other factors that can either lead to increased or decreased absenteeism due to sickness, including infection control measures in the home, or school specific factors such as local hygiene measures, equipment, geographic location, etc.

Description of the intervention

Rinse‐free hand wash (also known as hand gel, hand foam, hand sanitizer or hand rub) is increasingly being used in both healthcare settings and the community as a measure to improve hand hygiene (Gould 2017; Harbarth 2002; Maury 2000). The active ingredients of the majority of rinse‐free hand wash products are alcohols (such as isopropanol, ethanol, or n‐propanol). Other rinse‐free antimicrobial hand washes are not as common (Boyce 2002; Meadows 2004; Morton 2004). Some evidence suggests there are only minimal adverse effects (e.g. dry skin or irritation) associated with the use of rinse‐free hand wash (Meadows 2004; Sandora 2005); while some studies have shown rinse‐free hand wash reduces skin irritation and dryness compared to traditional soap and water methods, and has been shown to be more acceptable than traditional methods (Boyce 2000); however, single studies are not considered a reliable source of evidence for policy or practice. Rinse‐free hand wash with a concentration of ethanol between 60% and 95%, with a 3 mL to 5 mL application, is considered to be effective and safe for reducing the amount of bacteria present on the hand (Kampf 2008).

Rinse‐free hand wash can be considered as more convenient than traditional hand washing with soap and water for the following reasons: (1) it can be easily transported or carried on oneself; (2) it can be located within classroom or day care settings without the need for running water; (3) hands do not require traditional paper‐towel or air blower drying after use; and (4) it is quicker to complete than traditional hand washing. As rinse‐free hand wash may be a simpler method for hand hygiene compared to conventional hand washing with soap and water, it may be more effective than traditional measures. Rinse‐free hand wash may be applied by the children themselves, by a helper or under the direction of a helper, and may be implemented alongside an educational initiative to promote hand hygiene. For this review, education alone was not considered an intervention.

How the intervention might work

Respiratory‐tract viruses, such as influenza or rhinoviruses, are commonly spread between people through direct contact with droplets or aerosol containing the pathogen to the respiratory mucosa of another person (Heikkinen 2003; Musher 2003; Warren‐Gash 2013). Gastrointestinal illnesses and diarrhea‐causing pathogens are transmitted via the faecal‐oral route, by exposure to faecal matter, direct contact with a person, or via ingestion of food and water contaminated with faecal matter (Warren‐Gash 2013).

Hand hygiene is commonly recommended as a decontamination measure to reduce transmission via direct contact of gastrointestinal and respiratory infections and has shown promise in community settings (Aiello 2008; Warren‐Gash 2013). Once the hands come into contact with a pathogen, this can be transferred to respiratory or oral mucosa when the person brings their hand to their face. Hand hygiene may reduce transmission through reducing and removing or eliminating pathogens from the hand (Ejemot‐Nwadiaro 2015; Warren‐Gash 2013).

The active component of the vast majority of rinse‐free hand washes is alcohol. Alcohol has the ability to denature proteins, and therefore, acts as a skin disinfectant against viruses and bacteria (Bessonneau 2010). However, there may be a range of costs associated with its use, related to, for instance, perceptions and compliance, and financial cost, which we discuss in the Discussion section.

Why it is important to do this review

When children acquire an illness, this can spread through the family and result in days lost from school, and from work. Student school attendance is positively related to improved performance on standardized tests (Lamdin 1996), whilst significant or chronic absence from schooling can have a detrimental effect on a student's academic achievement (Chang 2008). Although lost days to an infectious illness like the common cold or gastroenteritis are not likely to result in a significant amount of attendance days lost from school, as compared to a chronic illness, there may still be an effect on learning and academic achievement (Gottfried 2009).

A Cochrane systematic review (Ejemot‐Nwadiaro 2015), which evaluated hand washing with water and soap to reduce diarrhea in children and adults in community settings (day care centres, schools, communities or hospitals) in both high‐income countries and low‐ and middle‐income countries (LMICs), found a reduction in diarrhea episodes of "around one‐third (rate ratio 0.70; 95% CI 0.58 to 0.85)" (Ejemot‐Nwadiaro 2015). However, the authors explicitly excluded rinse‐free hand wash as an intervention and respiratory illnesses as an outcome (Ejemot‐Nwadiaro 2015). Another systematic review, published in 2004, evaluated the effectiveness of rinse‐free hand sanitizers for reducing absenteeism related to illness in elementary school children. The review authors found six trials of low quality and poor reporting (Meadows 2004). Since that review there have been a number of new studies published. A systematic review was published in 2016 on hand hygiene interventions for children in educational settings (Willmott 2016). The authors of this review concluded that the evidence is equivocal regarding the effectiveness of hand hygiene interventions although they may decrease respiratory tract infections amongst children. There are some important differences between our review inclusion criteria and the Willmott 2016 review, the main being that our review focuses explicitly on rinse‐free interventions. Willmott 2016 stated the following as one of the limitations of their review: this "review does not distinguish between handwashing with soap or hand sanitizer use even though these methods may have different resource implications and be differentially effective in eliminating certain pathogens.” Additionally, the search for the Willmott 2016 review was conducted in September 2014 and there have been a number of new studies published after this date. Given the convenience of rinse‐free hand washing compared to traditional approaches, the number of recent dedicated studies addressing rinse‐free hand wash, and the potential policy implications for hand hygiene practices, a review on rinse‐free hand wash in preschools and schools is required.

This systematic review aims to provide an up‐to‐date examination of the effects of rinse‐free hand wash on illness‐related absenteeism amongst preschool and school children in low‐, middle‐ and high‐income countries.

Objectives

1. To assess the effectiveness of rinse‐free hand washing for reducing absenteeism (due to illness or for any reason) in preschool and school children compared to no hand washing, conventional hand washing with soap and water or other hand hygiene strategies.

2. To determine which rinse‐free hand washing products are the most effective (if head‐to‐head comparisons exist), and what effect additional strategies in combination with rinse‐free hand washing have on the outcomes of interest.

Methods

Criteria for considering studies for this review

Types of studies

Randomized controlled trials (RCTs), including cluster‐RCTs, irrespective of publication status. We also considered for inclusion quasi‐RCTs, where allocation has been systematic but not random (for example, by days of the week).

Types of participants

Children aged between two and 18 years attending preschool (childcare, day care, kindergarten, etc.), or school (primary, secondary, elementary, etc.). We included children attending preschool or school in urban or rural settings regardless of whether they reside in a low‐, middle‐ or high‐income country.

Types of interventions

Rinse‐free hand wash in any form (hand rub, hand sanitizer, gel, foam etc.), based on alcohol or another active ingredient, irrespective of dose or frequency of use.

It may be used alone or as part of a comprehensive hand hygiene program that includes, for example, education on rinse‐free hand wash as an intervention. The rinse‐free hand wash may be applied by the child or by a helper (such as a childcare worker, caregiver or teacher) or under direction of the helper.

Comparators included conventional hand washing with soap and water, other hand hygiene programs (such as education alone), or no intervention.

Types of outcome measures

Primary outcomes

1. Student absenteeism for any reason. Absenteeism is defined as time absent from preschool or school when the student is scheduled to be attending, and does not include planned holidays or leave, or student‐free days.

2. Student absenteeism due to any illness.

3. Adverse skin reactions (such as a rash or irritation) within the trial period.

Illness may be confirmed by a physician or by self‐report.

The outcome measures could be assessed on a per week, month, term, trial period, or year basis. These could be reported as average or median days absent per group, as total days absent within each group, or as an incidence rate (i.e. two absences per 100 student days) per group. This is not a time‐bound intervention and, as such, outcomes will not be reported in terms of short‐term, mid‐term and long‐term follow‐up.

Secondary outcomes

1. Child or student absenteeism due to acute respiratory illness (an infection of the respiratory system such as influenza or rhinovirus).

2. Child or student absenteeism due to acute gastrointestinal illness (an illness with gastrointestinal symptoms such as diarrhea, vomiting and nausea).

3. Compliance with the intervention or program.

4. Perception of the hand hygiene strategy or satisfaction with the hand hygiene strategy.

Search methods for identification of studies

Electronic searches

The following electronic databases were searched initially in November 2016, and top‐up searches were performed in February 2019 and February 2020.

1. Cochrane Central Register of Controlled Trials (CENTRAL; 2020 Issue 2) in the Cochrane Library, and which includes the Cochrane Developmental, Psychosocial and Learning Problems Specialised Register (searched 19 February 2020).

2. MEDLINE Ovid (1946 to 1 February 2020).

3. MEDLINE In‐Process & Other Non‐Indexed Citations Ovid (searched 19 February 2020).

4. MEDLINE Epub Ahead of Print Ovid (searched 19 February 2020).

5. Embase Ovid (1974 to 18 February 2020).

6. CINAHLPlus EBSCOhost (Cumulative Index to Nursing and Allied Health Literature; 1937 to 19 February 2020).

7. ERIC EBSCOhost (Education Resources Information Center; 1966 to 19 February 2020).

8. Science Citation Index Web of Science (SCI; 1970 to 19 February 2020).

9. Social Sciences Citation Index Web of Science (SSCI; 1970 to 19 February 2020).

10. Conference Proceedings Citation Index ‐ Social Science & Humanities Web of Science (CPCI‐SS&H; 1990 to 19 February 2020).

11. Conference Proceedings Citation Index ‐ Science Web of Science (CPCI‐S; 1990 to 19 February 2020).

12. LILACS (Latin American and Caribbean Health Sciences Literature; lilacs.bvsalud.org/en; searched 19 February 2020).

13. Cochrane Database of Systematic Reviews (CDSR; 2020 Issue 2), part of the Cochrane Library (searched 22 February 2020).

14. Database of Abstracts of Reviews of Effects (DARE; 2015 Issue 2; final issue searched 3 November 2016), part of the Cochrane Library. Archived version available at www.york.ac.uk/crd).

15. Epistemonikos (www.epistemonikos.org; searched 19 February 2020)

16. Database of Promoting Health Effectiveness Reviews (DoPHER; eppi.ioe.ac.uk/webdatabases4/Intro.aspx?ID=9; searched 22 February 2019).

17. ClinicalTrials.gov (clinicaltrials.gov; searched 2 March 2020)

18. World Health Organization International Clinical Trials Registry Platform (WHO ICTRP; apps.who.int/trialsearch; searched 2 March 2020).

19. Australian New Zealand Clinical Trials Registry (www.anzctr.org.au; searched 2 March 2020).

The search strategies used for each source are available in Appendix 1. We did not place any language restrictions on the search and we assessed non‐English studies for their need for translation on a case‐by‐case basis (Higgins 2011a).

Searching other resources

We searched the reference lists of studies selected for inclusion for additional references and made direct contact with lead authors of studies to collect additional information as required.

Data collection and analysis

We reported only the methods we used. Other pre‐planned methods (Munn 2017) are reported as in Table 2.

1. Unused methods.

Section of review	Unused methods	Justification
Electronic searches	We had planned to search International Initiative for Impact Evaluation (3ie) Systematic Reviews Database.	We did not search International Initiative for Impact Evaluation (3ie) Systematic Reviews Database as planned.
Measures of treatment effect	Time‐to‐event data We had planned to analyze time‐to‐event data as dichotomous data, where appropriate. If hazard ratios had been reported and had been suitable for synthesis, we planned to compute RR for other similar studies, so that a synthesis across studies could occur.	Due to the reporting of the data in the primary studies, this did not eventuate.
	Continuous data As absenteeism can occur on multiple occasions, it may have been that mean days absent were reported. We had planned to calculate effect sizes as mean differences and to present these with 95% confidence intervals. If different scales had been used, we had planned to report effect sizes using standardized mean differences (SMD).	Absenteeism was not reported in any of the papers as continuous data.
Assessment of reporting biases	If there had been an adequate number of studies (at least 10), we would have created funnel plots to investigate reporting bias (Sterne 2011). In the case of 10 or more studies, for continuous data, we would have used Egger's test (Egger 1997).	We did not have any analyses that included 10 or more studies.
	If effect sizes appeared to depend on the size of the trial, we would have explored whether this association was due to heterogeneity or publication bias.	We did not have enough studies to adequately investigate small study effects and publication bias.
Subgroup analysis and investigation of heterogeneity	We had intended to explore heterogeneity by conducting the subgroup analyses listed below. 2. The frequency of the intervention (i.e. only after meals, before and after meals and toilet breaks, on arrival at preschool or school, etc.). 3. The person delivering the intervention or responsible for the intervention (teachers or caregivers compared to a child‐initiated intervention). 4. The means of recording absence (teacher reported compared to other measures). 5. The provision of hand‐wash alone versus the provision of hand wash plus additional strategies (such as education). 6. By gross national income per capita, based on World Banks classification of low‐, middle‐ and high‐income countries.	Insufficent details or information was able to be extracted from the included studies, preventing subgroup analysis.
Sensitivity analysis	We had intended to carry out sensitivity analyses, when necessary, to assess the robustness of our results to the exclusion of studies at high risk of bias (determined by both the allocation concealment and blinding of outcome assessment 'Risk of bias' criteria being rated as high)	All studies were at an overall high risk of bias; therefore, we did not perform this sensitivity analysis.

Selection of studies

We collated and uploaded all identified citations to the review management software, Covidence (Covidence), removing any duplicates. Two review authors (from ZM, CT, CL, CS, TB) then independently screened titles and abstracts for assessment against the inclusion criteria for the review (Criteria for considering studies for this review). We obtained the full text of any paper that was clearly eligible for inclusion or where there was any doubt about eligibility. Two review authors (from ZM, CT, CL, CS, TB) independently assessed the full text against the inclusion criteria. We excluded full‐text reports that did not meet the inclusion criteria and provide reasons for exclusion in the review and in the 'Characteristics of excluded studies' tables. Any disagreements that arose between the review authors were resolved through discussion, or with a third, independent review author (from either ZM, CT, CL, CS, TB). We recorded our decisions in a study flow diagram Figure 1 (Moher 2009).

1.

PRISMA study flow diagram.

Data extraction and management

Two review authors from the review team (from ZM, CT, CL, CS, TB) independently extracted data from included studies using a standardized data extraction tool. This tool was piloted and modified accordingly in Covidence. We extracted specific data on the population, intervention, study methods and outcomes of significance to the review question and specific objectives, as listed below.

1. Participants: number randomized (including the number of withdrawals and whether data were imputed and the imputation method), age distribution, gender, type of schooling, class sizes, time or months of the year (season), sociodemographics (race, ethnicity, language spoken) and country.

2. Intervention: the rinse‐free hand wash manufacturer, composition, active ingredient, dosage or frequency, application (who delivered it) and, when possible, cost and length of study. Details around any education regarding the use of the rinse‐free hand wash such as who delivered the education and the format for delivery (online or in person) was also extracted for each treatment group.

3. Outcomes: outcome definition and unit of measurement (such as how absence was measured), the number of participants allocated to each group, the sample size for each outcome.

4. Results: events per groups and subgroups.

Any disagreements that arose between the review authors were resolved through discussion, or with a third review author (from either ZM, CT, CL, CS, TB).

Assessment of risk of bias in included studies

Two independent review authors from the review team (from ZM, CT, CL, CS) critically appraised selected studies at the outcome level for risk of bias as detailed in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011a). This tool assesses the following domains of bias; selection (random sequence generation and allocation concealment), performance, detection, attrition, reporting and other sources of bias. We assessed the domains as high, low or unclear risk of bias, following the guidance in Table 8.5.d in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011a), and as described in Appendix 2. Any disagreements that arose between the review authors was resolved through discussion, or with a third, independent review author (from ZM, CT, CL, CS, TB). We report the results of the this appraisal in the Risk of bias in included studies section.

Measures of treatment effect

We pooled studies, where possible, in a statistical meta‐analysis using Review Manager 5 (RevMan 5) (Review Manager 2014).

Dichotomous data

We collected dichotomous data such as reporting whether a student was absent or not, the amount of student days absent out of total days, and the amount of absent episodes. This was sometimes reported with the raw numbers and other times as an incidence rate ratio (IRR), which was also extracted. For adverse event data, we extracted this and calculated effect sizes as risk ratio (RR) and present these with 95% confidence intervals (CIs). Where there were no events in a treatment arm, Review Manager 2014 added a fixed value of 0.5 to the empty cell. If there were no events in the study, the study was excluded from the meta‐analysis (Higgins 2011b). As specified in the protocol (Munn 2017), we planned to analyze time‐to‐event data as dichotomous data, where appropriate, and if hazard ratios were reported and suitable for synthesis, we planned to compute RR for other similar studies, so that a synthesis across studies could occur. However, due to the reporting of the data in the primary studies, this was not undertaken (see Table 2).

Unit of analysis issues

Cluster‐randomised trials

We were likely to encounter unit of analysis issues in this systematic review, as groups of individuals were likely to be randomized and assigned together (in clusters such as classrooms or schools) (Higgins 2011b). We attempted to take appropriate measures to address unit of analysis issues, such as using the generic inverse variance method in Review Manager 2014, when studies analyzed their data and providing adjusted estimates accounting for their cluster design. It was likely that study authors would have taken steps to control for clustering in their analysis; however, if not, we requested the individual participant data to calculate an estimate of the intracluster correlation coefficient (ICC). However, these data were not provided, and as such, we either used the IRR provided by the study or calculated our own based on the data provided in the report.

Dealing with missing data

We requested missing or additional data from authors of studies, where required. Where authors could be contacted or did not respond to requests, we have highlighted this in the Results section of the review. We did not impute missing data with replacement values. We analyzed only available data. However, where possible, we made calculations based on available data or effect sizes to enable subsequent meta‐analysis. This is described on a per study basis in the Effects of interventions section. We have addressed the potential impact of missing data in the Discussion section of the review (Higgins 2011a).

Assessment of heterogeneity

We assessed clinical and methodological heterogeneity by evaluating the similarities and differences across studies in terms of the population (including age ranges, urban or rural, country (including low‐ and middle‐income countries compared to high‐income countries) and type of schooling), the intervention (dose and frequency), and study design. We assessed statistical heterogeneity visually by inspection of the forest plot and statistically by Cochran's Q (P value ≤ 0.10), and by I², which is a statistic used for quantifying inconsistency in meta‐analysis. In our meta‐analyses which use a random‐effects model, we also report tau², an estimate of between‐study variability. We interpreted the I² according to the guidance in theCochrane Handbook for Systematic Reviews of Interventions, bearing in mind the limitations of concrete thresholds for I² (Deeks 2011):

1. 0% to 40%: might not be important;

2. 30% to 60%: may represent moderate heterogeneity;

3. 50% to 90%: may represent substantial heterogeneity; or

4. 75% to 100%: considerable heterogeneity.

Assessment of reporting biases

To address publication bias, we sought both published and unpublished literature. Too few studies were included to allow for the creation of a funnel plot to investigate reporting bias (Sterne 2011).

Data synthesis

Regardless of how the data were reported in the included studies (such as average or median days absent per group, as total days absent within each group, or as an incidence rate (e.g. two absences per 100 child days per group), we transformed the data to a common effect size, where possible, to facilitate meta‐analysis, as specified in the protocol (Munn 2017). For absenteeism, we used incidence rate ratios (IRRs) in the majority of cases, except for the comparisons evaluated in Pandejpong 2012 where rate difference was reported. This often required calculation of an IRR from the raw data, which was completed using StatsDirect software. For adverse effects, we used relative risks.

As we intended to generalize the results beyond the included studies, we used the random‐effects model as the default model, as this is a more appropriate approach than the fixed‐effect model for this purpose (Tufanaru 2015). We used the inverse variance method, available in Review Manager 2014, for both dichotomous and continuous data. We only used the fixed‐effect model when it was not appropriate to use the random‐effects model (for example, where fewer than five studies were included in the meta‐analysis) (Cooper 1994; Guolo 2017; Murad 2015; Tufanaru 2015).

We synthesized the data in a meta‐analysis when they were clinically comparable, and presented them in forest plots using Review Manager 2014, where possible. When synthesis in a meta‐analysis was not possible, due to significant clinical or methodological heterogeneity, we provided a narrative description of the results.

Summary of findings

We created a 'Summary of findings' table using GRADEPro GDT software (GRADEpro GDT 2016), based on review data exported from Review Manager 2014, for the following comparison: rinse‐free hand wash compared to no rinse‐free hand wash program for reducing absenteeism among preschool and school children. Following the GRADE approach (Schünemann 2011; Schünemann 2013), two authors from the review team (ZM, CL, CS, TB) assessed the certainty of the evidence for both the primary and secondary outcomes, based on the risk of bias, directness, heterogeneity, precision and risk of publication bias. We present the following information in the 'Summary of findings' table, when appropriate: absolute risks for the treatment and control, estimates of relative risk, and a ranking of the certainty of the evidence.

Subgroup analysis and investigation of heterogeneity

In order to explore heterogeneity, we subgrouped the data according to the age of the children (coinciding with level of education). According to our protocol (Munn 2017) we also planned to subgroup based on the frequency of the intervention; the person delivering the intervention; the means of recording absence; the provision of hand wash alone versus the provision of hand wash plus additional strategies; and by gross national income per capita. The justification for not performing these subgroup analyses have been reported in Table 2.

Sensitivity analysis

We did carry out sensitivity analysis on all analyses presented in this review to investigate the impact of the type of model (fixed or random) on the overall estimate of effect. We did not do this for exclusion of studies at high risk of bias, as all studies were at an overall high risk of bias as reported in Table 2.

Results

Description of studies

Results of the search

We ran searches in December 2016, February 2019 and February 2020. In total, we retrieved 7351 records, 6632 records from the database searches and 719 records from other sources. The duplicates were removed in Covidence, leaving 4428 records that we screened by title and abstract. From these, we identified 4286 clearly irrelevant records. We retrieved 142 full‐text articles and from these included 19 studies (reported in 28 publications) in the review (Figure 1).

We contacted 15 of the authors for additional information. Despite following up all email addresses and searching for authors via Google, we were unable to make contact or never heard back from the authors of the following reports: Ban 2015; Lau 2012; Morton 2004; Pandejpong 2012; Pickering 2013; Prazuck 2010; Snow 2008; Uhari 1999; White 2001;Biswas 2019. Responses were received from Correa 2012 and Sandora 2008, both of whom provided clarification on the presentation of their data. Gerald 2012 also responded, confirming that they did not collect any data on absences. Lennell 2008 responded, clarifying to the review team that absences for reasons other than infectious illness were excluded from the analysis. These authors were also unwilling to share the individual participant data for ethical concerns. Finally, Vessey 2007 responded and provided the review team with the complete raw data set, which we used for the analyses presented in this review.

Included studies

This review includes 19 studies from 28 reports involving 30,747 patients. From the 19 trials, five provided data that did not contribute to any of the meta‐analyses. Study characteristics are reported in detail in the Characteristics of included studies tables and summarized below.

Study types

Of the 19 included studies, all were randomized trials other than the study by Lau 2012, which was a controlled trial. All 19 of the studies employed a cluster‐trial design. Three of the studies also used a cross‐over design (Gerald 2012; Morton 2004; Vessey 2007). The duration of the trials ranged from two months (White 2001) to 14 months (Uhari 1999). The sample size ranged from 253 (Morton 2004) to 10885 (Biswas 2019), with the average sample size across studies being 1618 (standard deviation (SD) = 2312).

Populations and Settings

There were more studies conducted in the USA (eight studies:Gerald 2012; Lau 2012; Morton 2004; Sandora 2008; Snow 2008; Stebbins 2011; Vessey 2007; White 2001 ) compared to any other single country. Spain was the only other country where multiple studies has been conducted (two studies: Azor Martinez 2014; Azor Martinez 2018). The rest of the studies were conducted in China (Ban 2015), Colombia (Correa 2012), Bangladesh (Biswas 2019), Finland (Uhari 1999), France (Prazuck 2010), Kenya (Pickering 2013), New Zealand (Priest 2014), Sweden (Lennell 2008) and Thailand (Pandejpong 2012).

In terms of the educational setting, six studies were conducted in preschools or day‐care centres (Azor Martinez 2018; Ban 2015; Correa 2012; Lennell 2008; Pandejpong 2012; Uhari 1999); the remaining 13 studies were conducted in elementary or primary schools (Azor Martinez 2014; Biswas 2019; Gerald 2012; Lau 2012; Morton 2004; Pickering 2013; Prazuck 2010; Priest 2014; Sandora 2008; Snow 2008; Stebbins 2011; Vessey 2007; White 2001). For the schools, it was not always clear whether they were conducted in public or private institutions, and two studies (White 2001 and Biswas 2019) included both. Five studies stated they were conducted in public settings (Azor Martinez 2014; Gerald 2012; Lau 2012; Snow 2008; Stebbins 2011).

Given the mix of day‐care centres and elementary schools, the overall age across studies included in this review ranged from birth (Azor Martinez 2018) to 13 to 14 years (Pickering 2013).

Interventions

Studies did not always specify the type of rinse‐free hand wash used. The most common, commercial organization was GOJO industries, named in four studies (Correa 2012; Gerald 2012; Pickering 2013; Stebbins 2011). Studies did not always provide the active ingredient/s, although where they were provided, most (13 studies) used ethanol (alcohol) at a range of 60% to 75% (Azor Martinez 2014; Azor Martinez 2018; Ban 2015; Biswas 2019; Correa 2012; Gerald 2012; Lennell 2008; Morton 2004; Pandejpong 2012; Prazuck 2010; Priest 2014; Sandora 2008; Stebbins 2011). Two studies, Lau 2012 and White 2001, used a product from Woodward Laboratories Inc (CA, USA), where the active ingredient was benzalkonium chloride (stated at concentration levels of 0.13% in Lau 2012). In three studies, the hand sanitizer applied was unclear (Snow 2008; Uhari 1999; Vessey 2007).

The instructions and guidance for using the rinse‐free hand wash also differed across the studies. The study with the most strict application regimen was Pandejpong 2012, where participants were assigned to an intervention group of use every 60 or 120 minutes. The majority of the remaining studies provided a protocol or recommendations for when rinse‐free hand washing should be used. This commonly included: on presentation to the classroom or arrival at school (nine studies: Azor Martinez 2014; Azor Martinez 2018; Biswas 2019; Gerald 2012; Lau 2012; Morton 2004; Prazuck 2010; Stebbins 2011; White 2001); before or after (or both) mealtimes or scheduled breaks (13 studies: Azor Martinez 2014; Azor Martinez 2018; Biswas 2019; Gerald 2012; Lau 2012; Lennell 2008; Morton 2004; Prazuck 2010; Priest 2014; Sandora 2008; Stebbins 2011; Vessey 2007; White 2001); upon leaving for the day (six studies: Azor Martinez 2014; Azor Martinez 2018; Biswas 2019; Lau 2012; Stebbins 2011; White 2001); after coughing/sneezing or blowing/rubbing noses (eight studies: Azor Martinez 2014; Azor Martinez 2018; Biswas 2019; Gerald 2012; Lau 2012; Morton 2004; Priest 2014; White 2001); when a teacher asked them (one study: Morton 2004); after using the restroom (seven studies:Biswas 2019; Gerald 2012; Lennell 2008; Morton 2004; Prazuck 2010; Sandora 2008; Vessey 2007); after changing diapers (one study: Azor Martinez 2018); when dirty (two studies: Lennell 2008; Vessey 2007); after a field trip (one study: Lau 2012); or after using the gym/physical education lessons (two studies: Azor Martinez 2014; Lau 2012). Four studies did not specify a particular protocol or it was not described (Correa 2012; Pickering 2013; Snow 2008; Uhari 1999). In the case of one study, Ban 2015, it was simply stated that rinse‐free hand wash was used under supervision. All studies (with the exception of Pandejpong 2012) provided some form of education regarding hand hygiene or hand sanitizer use, in the form of either teacher‐ or researcher‐directed classroom lessons or presentations. In all studies, the children applied the rinse‐free hand wash themselves, although in six studies students may have been assisted by teachers or carers also (Azor Martinez 2014; Azor Martinez 2018; Correa 2012; Lennell 2008; Pandejpong 2012; Uhari 1999).

Outcomes

The main outcome, absenteeism, was reported and measured differently amongst the studies. Some of the studies (n = 4) stated that they relied on parental reporting to the school (Azor Martinez 2018; Lau 2012; Lennell 2008; Morton 2004), others (n = 11) in records kept by the school and collected by school personal (Azor Martinez 2014; Priest 2014; Sandora 2008; Stebbins 2011; Vessey 2007), by teachers using calendars or templates (Ban 2015; Pandejpong 2012; White 2001), student self‐reporting (Pickering 2013), or by parents using templates (Prazuck 2010; Uhari 1999). Absenteeism was not reported or it was unclear how it was reported in four studies (Correa 2012; Biswas 2019; Gerald 2012; Snow 2008).

The definition for diarrhea of three or more loose/watery stools in 24 hours (Ban 2015;Correa 2012; Pickering 2013), or a definition very similar (i.e. two watery stools in a 24‐hour period or three stools in 48 hours (Azor Martinez 2014; Pickering 2013; Prazuck 2010; Sandora 2008) was used in studies that have contributed outcome data towards gastrointestinal‐related absenteeism. Other studies (n = 13) also stated that a combination of particular symptoms, such as vomiting (Azor Martinez 2014; Priest 2014; White 2001), diarrhea (Ban 2015; Prazuck 2010; Priest 2014; White 2001), fever (Ban 2015; Prazuck 2010), abdominal pain (Ban 2015; Prazuck 2010; White 2001) and nausea (Prazuck 2010) could indicate gastrointestinal illness.

In studies that collected data on respiratory illness, one study used the Centers for Disease Control (CDC) definition for influenza‐like illness (Stebbins 2011). Whilst others (nine studies) stated a combination of symptoms could be diagnosed as a respiratory illness, symptoms considered included runny nose (Azor Martinez 2014; Azor Martinez 2018; Ban 2015; Correa 2012; Pandejpong 2012; Sandora 2008), blocked or stuffy nose (Azor Martinez 2014; Azor Martinez 2018; Ban 2015; Correa 2012; Pandejpong 2012; Priest 2014; Sandora 2008; White 2001), cough/expectoration (Azor Martinez 2014; Azor Martinez 2018; Ban 2015; Biswas 2019; Correa 2012; Pandejpong 2012; Priest 2014; Sandora 2008; White 2001), fever or chills (Azor Martinez 2014; Ban 2015; Biswas 2019; Correa 2012; Pandejpong 2012; Priest 2014; Sandora 2008; White 2001), sore throat (Azor Martinez 2014; Azor Martinez 2018; Correa 2012; Pandejpong 2012; Priest 2014; Sandora 2008), sneezing (Azor Martinez 2014; Azor Martinez 2018; Priest 2014; Sandora 2008; White 2001), ear pain (Correa 2012), bronchitis (White 2001), pink eye (White 2001), headache (Pandejpong 2012; Priest 2014; White 2001), and asthma exacerbation (White 2001).

Funding of studies

Not all studies reported their funding support. Of those that did, eight studies were funded by a commercial body who manufactures rinse‐free hand wash or who provided support or free samples for the duration of the study (Ban 2015; Correa 2012; Lau 2012; Morton 2004; Pickering 2013; Prazuck 2010; Sandora 2008; Vessey 2007).

Excluded studies

Following the full‐text review of 142 reports, we excluded 114 reports, 51 of which were excluded as they were either duplicates or irrelevant. The reasons for the exclusions of the remaining 63 reports (58 studies) are described in the Characteristics of excluded studies tables, but were mainly due to studies using interventions that were incompatible with the review question.

Risk of bias in included studies

We assessed risk of bias using the Cochrane 'Risk of bias' tool. For further information of individual studies' risk of bias, please see Characteristics of included studies tables. For 'Risk of bias' summary figures, see Figure 2 and Figure 3.

2.

'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

3.

'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.

Allocation

Random sequence generation

Of the studies, 10 demonstrated a low risk of bias for this domain (Azor Martinez 2014; Azor Martinez 2018; Biswas 2019Correa 2012; Gerald 2012; Lennell 2008; Priest 2014; Sandora 2008; Stebbins 2011; Uhari 1999). For these studies the method of randomization was clearly described by the study authors. Seven studies (Morton 2004; Pandejpong 2012; Pickering 2013; Prazuck 2010; Snow 2008; Vessey 2007; White 2001) were assessed as being unclear as the authors stated that randomization occurred, however the specific method of randomization was not specified. Two studies were at high risk of bias for this domain (Ban 2015; Lau 2012). The Ban 2015 study included only two kindergartens and it was unclear how (and if) randomization actually occurred. Consequently, we rated it as high risk. The Lau 2012 study was a controlled study where allocation was systematic but not random and as such, this was also judged to be at a high risk.

Allocation concealment

In cluster‐randomized trials, clusters are often randomized and allocated at the same time, meaning there is likely to be a low risk of bias related to allocation concealment (Higgins 2011a). As such, if a study provided sufficient details as to how randomization of the sequence occurred (therefore judged as being at a low risk of bias ‐ as above), it was regarded as low risk. The exception to this was the study by Sandora 2008, even though this study was at low risk of bias for random sequence generation, it is not clear whether the investigators were unaware of the allocation schedule prior to recruitment and selection of groups, thus being judged as an unclear risk of bias. To summarize, nine studies (Azor Martinez 2014; Azor Martinez 2018; Biswas 2019; Correa 2012; Gerald 2012; Lennell 2008; Priest 2014; Stebbins 2011; Uhari 1999) were judged as being at low risk, and eight studies were judged as being at an unclear risk (Morton 2004; Pandejpong 2012; Pickering 2013; Prazuck 2010; Sandora 2008; Snow 2008; Vessey 2007; White 2001). Allocation concealment was judged to be a potential concern in two studies where randomization was deemed an issue and as such were judged as being at high risk (Ban 2015; Lau 2012).

Blinding

Performance bias

Due to the nature of the intervention used it was often difficult to blind participants (students; school staff and parents), and as such, all but one study was judged to have been at a high risk of performance bias. Only one study, White 2001, performed adequate blinding of participants through the use of a placebo hand wash which is to be expected for this type of intervention. As such, this was the only study judged to be at a low risk of bias.

Detection bias

Of the studies, only two adequately blinded outcome assessors/reporters (Priest 2014; Sandora 2008). This was achieved in the Priest 2014 study by having telephone interviewers collecting data who were blinded to the group allocation until after the analysis was complete. Similarly, in the Sandora 2008 study, the person collecting data on absences was also blinded. Fifteen studies were at a high risk of bias. Thirteen of these (Azor Martinez 2014; Azor Martinez 2018; Biswas 2019; Correa 2012; Lennell 2008; Lau 2012; Morton 2004; Pickering 2013; Prazuck 2010; Stebbins 2011; Uhari 1999; Vessey 2007; White 2001) reported that the outcomes were recorded by either the parent, teacher or reported by study personnel themselves. As all of these people were unblinded in their respective studies, we have judged this to be at a high risk of bias. The other two studies (Ban 2015; Pandejpong 2012) were judged as being at high risk as they failed to provide sufficient information as to if the outcome assessors were blinded or not, however as these studies were also at high risk of performance bias, we have judged them to also have been at high risk of detection bias.Two studies were judged to have been at an unclear risk (Gerald 2012; Snow 2008) due to the study authors not providing enough information as to how the outcomes themselves were measured, thus precluding them from assessing how outcome assessors may, or may not have been blinded.

Incomplete outcome data

Six trials (Correa 2012; Gerald 2012; Lennell 2008; Priest 2014; Stebbins 2011; White 2001) were at a high risk of attrition bias, all these studies experiencing large losses to follow‐up and high drop out rates. Nine studies were judged to be at a low risk of bias. Of these, seven studies (Azor Martinez 2014; Azor Martinez 2018; Ban 2015; Lau 2012; Morton 2004; Pandejpong 2012; Uhari 1999) did experience loss to follow‐up, however these losses were relatively small and were evenly balanced between treatment groups. Three studies (Biswas 2019; Prazuck 2010; Sandora 2008), also judged to be at low risk of attrition bias reported that no or minimal losses to follow‐up were experienced in the study. Three studies (Pickering 2013; Snow 2008; Vessey 2007) were judged to be at a unclear risk of bias, as insufficient information was provided by the authors in regards to participant flow within the study and whether losses to follow‐up were experienced.

Selective reporting

Fourteen studies (Azor Martinez 2014; Azor Martinez 2018; Ban 2015; Biswas 2019; Correa 2012; Gerald 2012; Lau 2012; Morton 2004; Pickering 2013; Priest 2014; Sandora 2008; Stebbins 2011; Vessey 2007; White 2001) were at low risk of reporting bias, as they provide full and complete reporting of all pre‐specified outcomes, or when a protocol could not be retrieved, all outcomes as specified in the methods section were included in the results. Finally, five studies (Lennell 2008; Pandejpong 2012; Prazuck 2010; Snow 2008; Uhari 1999) were judged to be unclear, as a study protocol could not be retrieved, and insufficient information was provided in the text to allow for a low judgment.

Other potential sources of bias

Eleven studies (Azor Martinez 2014; Azor Martinez 2018; Ban 2015; Gerald 2012; Lau 2012; Lennell 2008; Morton 2004; Prazuck 2010; Uhari 1999; Vessey 2007; White 2001) were judged to be at high risk for other potential sources of bias. Potential sources of bias that could pose additional risk include: when there is clear imbalance in baseline characteristics between groups (for cross‐over trials), loss of clusters in cluster trials, incorrect analysis (such as not accounting for clustering), or evidence of individuals being preferentially recruited to clusters following the randomization of clusters (Higgins 2011a). In the studies by Ban 2015 and Gerald 2012, there were important differences in baseline characteristics between groups. In the Lennell 2008 study, clusters were lost during the trial. In the Morton 2004 and White 2001 studies, which were both crossover trials, there was insufficient washout periods (1‐2 weeks). Finally, the Prazuck 2010 and Uhari 1999 studies did not take into account clustering in their analysis, additionally, as we calculated crude incident rate ratios (IRRs) for Azor Martinez 2014; Azor Martinez 2018; Ban 2015; Lau 2012; Pickering 2013; Prazuck 2010; Vessey 2007; White 2001, this was considered as a risk of bias. Morton 2004 also used an insufficient washout period in their study. Seven studies (Biswas 2019; Correa 2012; Pandejpong 2012; Pickering 2013; Priest 2014; Sandora 2008; Stebbins 2011) were judged at low risk of other potential bias, and only one study (Snow 2008) was at an unclear risk. This was due to the overall poor reporting quality of this paper that precluded a judgment of either high or low.

Effects of interventions

See: Table 1

Rinse‐free hand wash versus control

Sixteen studies were included in this comparison (Azor Martinez 2014; Azor Martinez 2018; Ban 2015; Correa 2012; Gerald 2012; Lennell 2008; Morton 2004; Pickering 2013; Prazuck 2010; Priest 2014; Sandora 2008; Snow 2008; Stebbins 2011; Uhari 1999; Vessey 2007; White 2001) All rinse‐free hand wash use was supplemented with an educational regimen that focused on the importance of hand washing and infection control. Some studies also included direct instruction for rinse‐free hand wash usage. The particular details of these concurrent activities is expanded for each outcome. In all but three studies (Azor Martinez 2014; Ban 2015; Sandora 2008), rinse‐free hand wash provision was compared against normal practice supplemented with an educational regimen or activities that encouraged good hand hygiene. Where possible, we calculated and presented the number of total possible study days (henceforth referred to as child‐days possible) in appropriate meta‐analyses. Due to the significant heterogeneity between studies in how they reported their outcomes, we provide specific details for each study below. Where studies did not report the age distribution of the participating children, we have made estimates based on the year levels included and the geographical location the trial took place. A summary of these results can be found in Table 1.

Primary outcomes

Child or student absenteeism for any reason

Two studies contributed data towards this outcome (Priest 2014; Stebbins 2011). Both studies reported an incidence rate ratio (IRR) of absence episodes against the child‐days possible. The provision of rinse‐free hand wash was not effective at reducing the incidence rate of absenteeism for any reason compared to control (IRR 0.91, 95% confidence interval (CI) 0.82 to 1.01, P = 0.07; very low‐certainty evidence; Analysis 1.1). There may be some issues with heterogeneity between studies (Chi² = 2.43, P = 0.12, I² = 59%).

1.1. Analysis.

Comparison 1 Rinse‐free hand wash versus control, Outcome 1 Absenteeism for any reason.

Child or student absenteeism due to any illness

Six studies contributed data towards this outcome Ban 2015; Lennell 2008; Pickering 2013; Priest 2014; Vessey 2007; White 2001. The data presented in four of these studies (Ban 2015; Pickering 2013; Vessey 2007; White 2001) was subjected to transformation by the review team in order to convert to a common effect size. This process has been detailed in Appendix 3. When considering all groups, the combined effects show that provision of rinse‐free hand wash is effective in reducing the incidence of absenteeism as a result of any illness (IRR 0.82, 95% CI 0.69 to 0.97, P = 0.02; very low‐certainty evidence; Analysis 1.2). We stratified the data by subgroups based on the age of children. The provision of rinse‐free hand wash was no more of less effective in reducing the incidence of absenteeism in students younger than five years, compared to control (IRR 0.76, 95% CI 0.55 to 1.07, P = 0.11). This was also the case for students aged five to 12 years old (IRR 0.92, 95% CI 0.75 to 1.14, P = 0.45). For each analysis, there was substantial heterogeneity between studies (Analysis 1.2.1: Chi² = 4.40, P = 0.04, I²=77%; Analysis 1.2.2: Chi² = 10.72, P = 0.005, I² = 81%; and Analysis 1.2.3: Chi² = 28.24, P < 0.001, I² = 82%). However, given the small number of included studies, this needs to be interpreted with caution. We conducted a sensitivity analysis on these data to investigate the choice of model used (fixed versus random). There was a difference for the subgroup of preschool age (< five years old), with an effect estimate for the fixed‐effect model of 0.85 (95% CI 0.78 to 0.94) and the random‐effects model of 0.76 (95% CI 0.55 to 1.07). We have presented the results for the random‐effects model as these are more conservative and align with the directive of the protocol (Munn 2017).

1.2. Analysis.

Comparison 1 Rinse‐free hand wash versus control, Outcome 2 Absenteeism due to any illness.

Adverse skin reactions

Pooled results

Three studies (n = 4365) contributed data towards this outcome (Azor Martinez 2014; Azor Martinez 2018; Priest 2014). This analysis has been further separated into subgroups based on the age of the participating students. For students aged birth and three years, there was no important difference in the occurrences of adverse skin reactions for those assigned to rinse‐free hand wash versus control (RR 2.64, 95% CI 0.11 to 64.59, P = 0.55). There was also no difference in students aged five to 11 years (RR 1.02, 95% CI 0.79 to 1.31, P = 0.89). The overall effect again, shows no important differences between groups (RR 1.03, 95% CI 0.80 to 1.32, P = 0.84 Analysis 1.3). There was no concern for heterogeneity between studies (Chi²= 0.34, P = 0.56, I² = 0%). Priest 2014 reported 115 students randomized to receive rinse‐free hand wash developed an adverse skin reaction, compared to 100 randomized to the control group. Azor Martinez 2014 reported that one child who received rinse‐free hand wash showed worsening atopic dermatitis and was excluded from the group, and no reactions were observed in the control group. A similar result was also reported in a later study by the same authors; one student with existing dermatitis on the hand showed an exacerbation while no adverse events were observed in controls (Azor Martinez 2018).

1.3. Analysis.

Comparison 1 Rinse‐free hand wash versus control, Outcome 3 Adverse skin reactions.

Single study results

The majority of studies only provided a narrative report of the findings on this outcome. Ban 2015 make no specific mention of adverse events, but state 15 children (control n = 9; intervention n = 6) were lost to follow‐up. No further detail was provided to determine if this loss was related to adverse events. Morton 2004 reported that 10 children were removed from the study after developing skin irritations; however, as this was a cross‐over trial, the authors provided no detail as to what arm these students were in at the time the skin irritation developed. In the study by Vessey 2007, one student withdrew due to both the rinse‐free hand wash and soap control being too irritating. White 2001 report that seven students were removed from the study post‐randomization, after teachers or parents, or both, reported changes in skin conditions such as chapping or redness, or both; however, no information is provided if these children were in the active rinse‐free hand wash or the placebo group.

No adverse events were reported in the studies by Correa 2012; Gerald 2012; Pickering 2013; Prazuck 2010 and Sandora 2008. While no adverse events were reported by Lennell 2008, there were 10 reports of side‐effects due to the discoloration of clothing. Adverse events were not discussed in Snow 2008; Biswas 2019; Stebbins 2011 and Uhari 1999.

Secondary outcomes

Child or student absenteeism due to acute respiratory illness

Six studies contributed data towards this outcome (Azor Martinez 2014; Azor Martinez 2018; Biswas 2019; Sandora 2008; Stebbins 2011; White 2001). The data presented in three of these studies was subjected to transformation by the review team in order to convert to a common effect size (Azor Martinez 2014; Azor Martinez 2018; White 2001). This process has been detailed in Appendix 3. The overall effect shows that the provision of rinse‐free hand wash reduces the incidence of absenteeism due to respiratory illness (IRR 0.79, 95% CI 0.68 to 0.92, P = 0.005; very low‐certainty evidence; Chi² = 27.45, P < 0.0001, I² = 82%; Analysis 1.4). We stratified the data based on the age of the participating students. For students aged between birth and three years, the provision of rinse‐free hand wash resulted in reduced respiratory illness‐related absenteeism (IRR 0.77, 95% CI 0.72 to 0.82, P < 0.001; 1 study). For primary school students (five to 14 years old), there was no observed effect (IRR 0.79, 95% CI 0.61 to 1.03, P = 0.08); however, statistical heterogeneity was identified (Chi² = 27.13, P < 0.001, I² = 85%). Once again, there are some concerns of heterogeneity between all included studies (Chi² = 27.45, P < 0.0001, I² = 82%). We conducted a sensitivity analysis on this data to investigate the choice of model used (fixed versus random). There was a difference for the subgroup of primary school age (five to 14 years old), with an effect estimate for the fixed effect model of 0.75 (95% CI 0.70 to 0.80), and the random‐effects model of 0.79 (95% CI 0.61 to 1.03). We have presented the results for the random‐effects model as these are more conservative and align with the directive of the protocol (Munn 2017).

1.4. Analysis.

Comparison 1 Rinse‐free hand wash versus control, Outcome 4 Absenteeism due to acute respiratory illness.

It is important to note, that Sandora 2008 report that 285 students underwent randomization (Figure 1 of primary literature), but this is inconsistent with the reporting of Table 1 (primary literature), which does not add up to 285 (292) and includes a footnote "numbers may not sum to group totals for all of the variables because of missing responses" (quote; control group says 144 but Figure 1 says 139). Due to the poor reporting by the study authors, these findings are unreliable. Additionally, for the Biswas 2019 study, only episodes of influenza like illness was presented, which we have used as a proxy for respiratory related absenteeism.

Absenteeism due to gastrointestinal illness

Four studies contributed data towards this outcome (Azor Martinez 2014; Prazuck 2010; Sandora 2008; White 2001). The data presented in two of these studies was subjected to transformation by the review team in order to convert to a common effect size (Prazuck 2010; White 2001). This process has been detailed in Appendix 3. The analysis shows that the provision of rinse‐free hand wash resulted in reduced incidence of absenteeism compared to the control groups (IRR 0.79, 95% CI 0.73 to 0.85, P < 0.00001; Analysis 1.5); however, there are some concerns over study heterogeneity (Chi² = 21.48, P < 0.001, I² = 86%). That being said, it should be noted that the control groups in Azor Martinez 2014 and Sandora 2008 did not provide any formal education program on hand washing, whilst both Prazuck 2010 and White 2001 did. Subgrouping was not pre‐specified in the protocol to occur based on the provision (or lack thereof) of co‐interventions within the comparison group. In addition, the findings presented in the study by Sandora 2008 are unreliable, for the same reasons as presented above.

1.5. Analysis.

Comparison 1 Rinse‐free hand wash versus control, Outcome 5 Absenteeism due to acute gastrointestinal illness.

Compliance with the hand hygiene strategy

Compliance with the intervention appeared to range from moderate to high compliance (9 studies, 10,749 participants; very‐low certainty evidence). No study authors reported substantial issues with compliance. The individual study results are discussed further below.

Ban 2015 reported the consumption of intervention products to evaluate compliance for the intervention group. Over the course of the study (20 September 2010 to 28 September 2011), the intervention group utilized 20,600 × 20 mL bottles of instant hand sanitizer. They also calculated the average person usage (mL used/person day) of rinse‐free hand wash as 1.4.

Biswas 2019 reported the number of handwashing events against the total number of handwashing opportunities as observed by a member of the study team. In 921 opportunities, school children in the intervention group washed their hands in 604 opportunities (66%). In 802 opportunities, school children in the control group washed their hands in 171 (21%). Of these handwashing opportunities, school children in the intervention group used hand sanitizer in 91% of the observed handwashing events. However, it is important to note, that a member of the study team was not present to observe every potential opportunity for school children to wash their hands and the data reported are simply those from when a study member observed a handwashing event towards the end of the intervention period. It was also reported that the average consumption of hand sanitizer per child was 4.3 mL (95% CI = 1.5 mL to 7.1 mL).

Lennell 2008 reported that use of rinse‐free hand wash varied among intervention day care centres. With total usage ranging from 19 L to 60 L per 50 children; the study authors estimated that students used the rinse‐free hand wash two to six times per day.

Prazuck 2010 reported that the 300 mL rinse‐free hand wash container was replaced three times on each table (roughly every four weeks) for each classroom fitted with the rinse‐free hand wash. This indicated to the study authors that compliance to the sanitization regimen was high.

There were limited data regarding compliance in the study by Priest 2014, who stated that they had to change their rinse‐free hand wash for 41 of the 396 classrooms, as some children had become reluctant to use the initial hand sanitizer product before eating their lunch, complaining of the taste of the sanitizer persisting on their fingers and food. A substitute was provided by the authors at week 10 of the study. This substitute had no ‘‘flavor’’ (quote) and both brands contained 60% ethanol. Following this change to the product, the median classroom difference in sanitizer usage between the first 10 weeks and the second 10 weeks (only in classrooms that switched products) was 2220 mL; the interquartile range of the usage difference was 2420 mL to 645 mL. All schools in the intervention group complied with the protocol of dispensing a volume equivalent to at least 45 mlLper child of hand sanitizer solution over the trial period. The average volume of hand sanitizer solution dispensed per child over the 34 schools was 94 mL.

Snow 2008 compared two forms of education with a control. In the control group, teachers simply instructed their students to “Wash your hands then line up for lunch” (quote). This was compared to teachers of classrooms who after instructing students to “Wash your hands then line up for lunch” (quote), walked over to the sink and began washing their hands (intervention one). The final intervention group was a guest educator teaching a 30‐minute grade‐appropriate lesson on hand hygiene principles and when rinse‐free hand wash is appropriate to use, coupled with the teacher demonstration that occurred in intervention one (intervention two). The study authors only reported outcome data on the rates of hand hygiene, each group (even controls) had access to the rinse‐free hand wash. The study authors reported narratively that both interventions one and two improved the rate at which alcohol‐based hand rubs (rinse‐free hand wash) were used for hand hygiene in children. However, each group (even controls) had some access to rinse‐free hand wash. These outcome data simply inform us that education improves use of alcohol‐based hand rubs in children, as recorded by the study authors.

Stebbins 2011 collected numerical outcome data regarding compliance. These results were reported in the earlier study (Stebbins 2010); however, these two individual papers reported on the same data set. Teachers were asked to complete surveys on their students' hand hygiene. Of the 16‐question survey, four questions were directly related to student compliance:

1. students wash hands more than three times a day;

2. students use hand sanitizer two times a day;

3. students use hand sanitizer four times a day; and

4. average number of times students wash/sanitize per day (direct report).

The study authors observed no difference between the mean scores for teacher observations for the rinse‐free hand wash group and control for questions one (rinse‐free hand wash: mean = 3.71 versus control: mean = 3.35, P = 0.042) and four (rinse‐free hand wash: mean = 3.95 versus control: 3.08, P = 0.144). However, teachers in the rinse‐free hand wash group observed their students using hand sanitizer at least twice a day (mean = 4.38) and four times a day (mean = 3.18), compared to controls (twice a day: mean = 2.82, P < 0.001; four times a day: mean = 1.89, P < 0.001).

In the study by Uhari 1999, the study nurse estimated in the course of her visits to the child day care centres that the children, in general, complied with all the instructions and washed their hands diligently. The compliance was calculated as the percentage of events where instructions were followed. The overall estimates of compliance varied from about 60% to 90% between the intervention day care centres, with a mean of 80%.

Of the 72 initial classes involved in the study by White 2001 (1626 student participants), 32 classes (16 active and 16 control; 769 student participants) were retained for analysis. The remainder of the classes were dropped from the data analysis because of noncompliance with minimum adequate product use standards (less than three uses per day).

Perception of the hand hygiene strategy

Teachers and students perceived rinse‐free hand wash positively and were willing to continue its use (3 studies, 1229 participants; very‐low certainty evidence). The individual study results are discussed further below.

Correa 2012 reported that all intervention centre teachers perceived the use of the alcohol‐based hand rubs (rinse‐free hand wash) as a more convenient hand hygiene method and manifested a willingness to continue its use.

Pickering 2013 conducted semi‐structured interviews with staff and students of participating schools. In regards to the perception of rinse‐free hand wash, 100% of teachers at intervention schools said they would prefer the permanent provision of rinse‐free hand wash over the provision of soap at their schools. One teacher stated that “I find it [sanitizer] easy to use than soap… If both were given, then you will find the hand sanitizer being used more than soap and water” (quote). For students, 91% stated that they would choose sanitizer to clean their hands over soap and water. Students at sanitizer schools reported that they perceived cleaning hands with rinse‐free hand wash to take a shorter time than hand washing with soap and water. Additionally, 80% of students in sanitizer schools said they disagreed with the statement that the sanitizer has an unpleasant odor, and 87% of students disagreed that using sanitizer made their hands feel dry.

Vessey 2007 conducted semi‐structured interviews with teachers to observe their perceptions of student rinse‐free hand wash use. No numerical data were available.

Many of the participants' observations indicated that they preferred the use of the hand sanitizer over soap and water as it better matched the pragmatics of the school day. The amount of time required was a key consideration, as noted in these comments: “....they [the students] would try to skip it [hand washing with soap and water] or wouldn't do it properly ...it took up to probably an extra 10 minutes to get out to lunch. I liked the hand sanitizer because it took so long to get the kids out to lunch [when hand washing with soap and water] and my kids would use it [hand sanitizer] because it was quick” (quote).

Improved adherence and better hand cleaning by students during the study period were also noted in teachers' comments:

1. “We have the sanitizer by the door and it was funny, the kids walk by it and subconsciously would just take a squirt...Lots of time I don't think they were paying attention to what they were doing”;

2. “It [hand sanitizer] was easy, it smelled good. It didn't make their food taste funny...in the lunchroom...”; and

3. “you can't let the water run...they touch [the faucet] with their dirty hands...touch it again with their clean hands...” (all direct quotes).

The ability to observe student behavior and maintain classroom decorum were other perceived benefits of hand sanitizers:

1. “We teach them a lot about coughing and sneezing into their hands and then to go wash their hands but many times they are in the classrooms and they can't leave. But if you have the gel, they can go over and use it.”; and

2. “When you have them go to in the bathroom with soap and water you can't tell if they are really using it...” (both direct quotes).

Rinse‐free hand wash and instruction versus rinse‐free hand wash and no instruction

One included study, Lau 2012, investigated the provision of rinse‐free hand wash with education and instruction versus rinse‐free hand wash provision alone. The data presented in this study were subjected to transformation by the review team in order to convert to a common effect size. This process has been detailed in Appendix 3.

Primary outcomes

Child or student absenteeism for any reason

There was no clear evidence of a difference with the provision of education and instruction with rinse‐free hand wash on the number of days spent absent for any reason (IRR 1.07, 95% CI 0.97 to 1.18, P = 0.18; Analysis 2.1).

2.1. Analysis.

Comparison 2 Rinse‐free hand wash with instruction versus rinse‐free hand wash with no instruction, Outcome 1 Absenteeism for any reason.

Child or student absenteeism due to any illness

The provision of education and instruction produced no effect on the incidence of absence days compared to no education or instruction (IRR 0.99, 95% CI 0.89 to 1.10, P = 0.86; Analysis 2.2)

2.2. Analysis.

Comparison 2 Rinse‐free hand wash with instruction versus rinse‐free hand wash with no instruction, Outcome 2 Absenteeism due to any illness.

Adverse skin reactions

This study did not report on adverse skin reactions.

Secondary outcomes

This study did not report on any of the secondary outcomes.

Rinse‐free hand wash every 120 minutes versus rinse‐free hand wash once before lunch

Only one study was included for this comparison (Pandejpong 2012), However, the overall reporting of these findings is poor. Attempts were made to contact the study authors and despite the study authors stating that there was no loss to follow‐up, they also stated that they only analyzed data for 538 of the 540 students randomized to the control group. The rates of absenteeism due to confirmed respiratory illness were 0.026 and 0.025 for the rinse‐free hand wash before lunch group and the rinse‐free hand wash every 120 minutes group, respectively. However, these data have mainly been presented as a rate difference, which has been inputted directly to RevMan 5 (Review Manager 2014) (as a risk difference (RD).

Primary outcomes

Child or student absenteeism for any reason

This study did not collect data on this outcome.

Child or student absenteeism due to any illness

This study did not collect data on this outcome.

Adverse skin reactions

The study reported narratively that no adverse events occurred during the study.

Secondary outcomes

Child or student absenteeism due to acute respiratory illness

For the rinse‐free hand wash every 120 minutes compared to rinse‐free hand wash at lunch time, there was no difference between the two interventions RD 0.001, 95% CI 0.0005 to 0.007 (Analysis 3.1).

3.1. Analysis.

Comparison 3 Rinse‐free hand wash every 120 minutes versus rinse‐free hand wash before lunch, Outcome 1 Absenteeism due to acute respiratory illness.

Perception of the hand hygiene strategy

Pandejpong 2012 stated that the usage of the hand sanitizer was reported by the authors as a seemingly enjoyable activity for the children.

Rinse‐free hand wash every 60 minutes versus rinse‐free hand wash every 120 minutes

One study, Pandejpong 2012, compared rinse‐free hand wash with instructions to use it every 60 minutes for one group (n = 452) and every 120 minutes in the another group (n = 447) .

Primary outcomes

Child or student absenteeism for any reason

This study did not collect data on this outcome.

Child or student absenteeism due to any illness

This study did not collect data on this outcome.

Adverse skin reactions

The study reported narratively that no adverse events occurred during the study.

Secondary outcomes

Child or student absenteeism due to acute respiratory illness

There was no difference between the two instruction regimens on absenteeism due to acute respiratory illness: RD 0.009, 95% CI 0.002 to 0.015 (Analysis 4.1).

4.1. Analysis.

Comparison 4 Rinse‐free hand wash every 60 minutes versus rinse‐free hand wash every 120 minutes, Outcome 1 Absenteeism due to acute respiratory illness.

Perception of the hand hygiene strategy

Pandejpong 2012 stated that the usage of the hand sanitizer was reported by the authors as a seemingly enjoyable activity for the children.

Rinse‐free hand wash every 60 minutes versus rinse‐free hand wash once before lunch

One study, Pandejpong 2012, compared rinse‐free hand wash with instructions to use it every 60 minutes for one group (n = 452) and before lunch for the other (n = 538)

Primary outcomes

Child or student absenteeism for any reason

This study did not collect data on this outcome.

Child or student absenteeism due to any illness

This study did not collect data on this outcome.

Adverse skin reactions

The study reported narratively that no adverse events occurred during the study.

Secondary outcomes

Child or student absenteeism due to acute respiratory illness

For rinse‐free hand wash every 60 minutes compared to rinse‐free hand wash at lunch, the RD was 0.0096 (95% CI 0.004 to 0.016; Analysis 5.1).

5.1. Analysis.

Comparison 5 Rinse‐free hand wash every 60 minutes versus rinse‐free hand wash before lunch, Outcome 1 Absenteeism due to acute respiratory illness.

Perception of the hand hygiene strategy

Pandejpong 2012 stated that the usage of the hand sanitizer was reported by the authors as a seemingly enjoyable activity for the children.

Discussion

Summary of main results

Our review found 19 studies that met the inclusion criteria with 30,747 participants across different types of schools in 11 countries. For the main outcome (child or student absenteeism for any reason), only two studies reported data. The pooled estimate for rinse‐free hand washing was incidence rate ratio (IRR) 0.91 (95% confidence interval (CI) 0.82 to 1.01; I² = 59%), with very low‐certainty evidence. For child or student absenteeism due to any illness, we included six studies in the meta‐analysis with a pooled IRR of 0.82 (95% CI of 0.69 to 0.97; I² = 82%), once again with very low‐certainty evidence. When evaluating child or student absenteeism due to acute respiratory illness, the pooled results from six studies was an IRR of 0.79 (95% CI 0.68 to 0.92; I² = 82%), very low‐certainty evidence. When evaluating child or student absenteeism due to acute gastrointestinal illness, the pooled estimate from four studies was IRR 0.79 (95% CI 0.73 to 0.85; I² = 86%), low‐certainty evidence. It did not appear that rinse‐free hand washing was associated with an important increase in skin reactions. Compliance with the intervention varied between moderate and high (9 studies, 10,749 participants; very‐low certainty evidence), and teachers and students perceived rinse‐free hand wash positively and were willing to continue its use (3 studies, 1229 participants; very‐low certainty evidence). Summarising the main results of this review, there was no evident impact on absenteeism for any illness; however, rinse‐free hand washing did appear to have a small and potentially beneficial effect on reducing overall illness‐related absenteeism and respiratory and gastrointestinal illness‐related absenteeism, and this effect may be more pronounced in a younger student cohort.

Overall completeness and applicability of evidence

In this review, we were able to address some our first objective, the effectiveness of rinse‐free hand washing for reducing absenteeism (due to illness or for any reason) in preschool and school children compared to no hand washing, conventional hand washing with soap and water or other hand hygiene strategies.

Although not many of our included studies addressed the main outcome of interest, substantially more investigated illness‐related absenteeism. Where statistically and clinically appropriate, we combined results across studies in meta‐analysis. To enable this pooling, at times, we needed to contact study authors to request their data in a different format; other times, we needed to use the data presented in the papers and convert these to a form suitable for pooling. Occasionally, the data were simply not accessible in a format that facilitated meta‐analysis, despite requests to study authors. Where possible, we chose to combine studies in this review in a meta‐analysis, although the interventions and settings differed somewhat in terms of their intensity, co‐interventions and settings. This enabled us to assess statistical heterogeneity between trials and also generate a pooled estimate of the effect for use in the 'Summary of findings' table and to inform practice.

Given the paucity of the evidence, we were unable to address our second objective for this review, where we aimed to determine which rinse‐free hand washing products are the most effective (if head‐to‐head comparisons exist), whether there is any supervision and what effect additional strategies in combination with rinse‐free hand washing have on the outcomes of interest. Studies did not always clearly report what the active ingredient was for the rinse‐free hand wash or the product name, or how it was applied.

In terms of applicability of the results of this review, the included trials were pragmatic rather than explanatory (Treweek 2009), taking place in real settings with reasonable inclusion and exclusion criteria. When considering the applicability of the interventions in the real world, most of the rinse‐free hand washing programs were accompanied by education sessions or material, with clear guidance on how (and when) it should be used. The intervention may be reasonably easy (and potentially convenient) to implement. Some of the advantages of rinse‐free hand washing were established by Vessey 2007, who stated that if schools do not have sinks in the classrooms, students must leave class every time their hands need washing; and they also mentioned the issues of appropriately adjusting the water temperature. Hand sanitizers are able to eliminate these problems. Additionally, Vessey 2007 noted that ease of dispenser installation, low malfunctioning rates, easy identification of need for refills, and dispenser placement (in a highly visible and readily accessible locations) are aspects that are important when a hand gel sanitizer is used. When considering applicability, it will also be important for end users to consider their own rates of gastrointestinal and respiratory illness, and consider whether the investment in rinse‐free hand washing is worth it based on the relatively small beneficial impact of the programs. In this review, the largest impact was seen for younger children and as such the intervention may be more justified for younger age groups. Importantly, rinse‐free hand wash may result in additional costs to any educational facility that will need to be considered in any implementation program.

Due to a lack of reporting (or poor reporting), it is difficult to judge the impact of rinse‐free hand washing on adverse events in our review. Other studies have noted similar concerns, and Morton 2004 noted that with rinse‐free products the primary risk is eye irritation if the gel gets in the eye. They also recommended that children with underlying eczema or other underlying chronic skin conditions do not use the gel. In addition, poor reporting made it difficult to assess the age of the children that participated in each study, and in some cases, age had to be estimated based on the region and year levels (or grade) that children belonged.

Students and teachers seem receptive to rinse‐free hand washing and compliance appears to be high, although there was minimal information in the included studies addressing compliance and how to address compliance. Uhari 1999 noted that the study nurse found that the children in intervention centres generally complied with all instructions and washed their hands diligently, especially on arrival and before eating, even without reminders. The overall estimates of compliance (compliance was calculated as the percentage of events where instructions were followed) varied from about 60% to 90% in the intervention centres, with a mean of 80%. Vessey 2007 reported that teachers preferred that the dispensers be placed in the classroom, or outside the restroom door, and also in the cafeteria area.

Quality of the evidence

Overall, the certainty of the evidence was either low or very low. For each outcome presented in the Table 1, we downgraded the certainty of the evidence for poor methodological quality. In terms of selection bias, neither randomization nor allocation concealment were a concern in many of the studies; however, there were obvious and understandable risks with regards to performance and detection bias across the studies. Only one study, White 2001, performed adequate blinding of participants by using a placebo formulation in the control group. We downgraded multiple outcomes for imprecision and, as such, further trials (especially investigating the main outcome of interest) are required. There were also multiple occurrences of inconsistency between study results contributing to an outcome. Additionally, there were concerns regarding detection bias, with 15 of the included studies being considered at high risk of bias for this domain, largely due to self‐reporting of outcomes. On no occasion did we downgrade an outcome for indirectness or publication bias.

Potential biases in the review process

We did not identify any potential biases in the review process. We conducted a comprehensive search for published and unpublished studies; we included studies in languages other than English; and we had two members of the team independently screen, select and extract data from studies.

Agreements and disagreements with other studies or reviews

There are other reviews that have a similar focus to ours, although this review is the first to focus specifically on all types of rinse‐free hand washing in schools and preschools. A review by Ejemot‐Nwadiaro 2015, which evaluated hand washing with water and soap to reduce diarrhea in children, found a reduction in diarrhea episodes of "around one‐third (RR 0.70; 95% CI 0.58 to 0.85)" (quote). Another systematic review, published in 2004, evaluated the effectiveness of rinse‐free hand sanitizers for reducing absenteeism related to illness in elementary school children. The review authors found six trials of low quality and poor reporting (Meadows 2004) and stated that although all included studies found a beneficial effect, the review authors could not say conclusively that the intervention was beneficial, due to the poor quality of included studies.

More recently, a systematic review was published in 2016 on hand hygiene interventions for children in educational settings (Willmott 2016). The authors of that review concluded that the evidence is inconsistent regarding the effectiveness of hand hygiene interventions, although they may decrease respiratory tract infections amongst children. Although this review did not focus explicitly on rinse‐free interventions they found a similar result to our review in that the intervention appears to have more benefit in younger children.

Authors' conclusions

Implications for practice.

This review has found that there is a small but potentially beneficial effect of rinse‐free hand washing on illness‐related absenteeism, with a potentially larger beneficial impact for younger children. However, we rated the results of this review for all outcomes as low or very low certainty according to the GRADE approach. When considering applying rinse‐free hand washing programs in local settings, there will need to be consideration of the age of the children and level of schooling in addition to the current rates of illness‐related absenteeism and whether the small, potentially beneficial effects seen here will translate into a meaningful reduction across their facility that will justify the added investment of implementing such a program. This is particularly important given the heterogeneity of the included studies in this review, from different countries, types of schooling, age of students, rates of absenteeism/illness, mode of delivery and frequency of application. In particular, the cost of the intervention, especially in low resource settings, needs careful consideration.

Implications for research.

Further research is required at all levels of schooling, pre‐school (from birth to four years), primary school (five to 13 years) and middle or high school (14+ years), evaluating rinse‐free hand washing programs to provide more conclusive evidence regarding the impact of these programs. These trials should include a suitable number of participants, and ensure that they appropriately adjust for clustering effects, including use of placebo interventions in control groups to account for risk of detection and performance bias. Overall absenteeism as well as specific illness‐related absenteeism should be assessed and studies shown ensure that they have rigorous data collection procedures in place to collect information on adverse events and skin reactions related to the intervention. The studies should clearly report the type of rinse‐free hand wash used, how it is applied (and whether there is any supervision), how compliance is measured, the active ingredient and any cost implications. Alongside hand washing, other aspects of school hygiene may also play an important role in preventing absenteeism. Future studies should consider investigating and recording aspects of school hygiene such as cleaning classrooms, tables and equipment. Current hygiene, sanitation and cleaning activities in practice at the time of the study for all groups investigated, and the time of year (e.g. season) when the study occurred, should be reported clearly also. Finally, studies should report standardized measures of compliance, adherence or satisfaction with the intervention.

Appendices

Appendix 1. Search Strategies

Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library

Searched 4 November 2016, 22 February 2019,19 February 2020

#1[mh "hand sanitizers"]
 #2[mh "hand hygiene"]
 #3[mh "hand disinfection"]
 #4(hand* near/3 (hygiene or wash* or wipe* or gel* or rub* or foam* or disinfect* or sanitis* or sanitiz*)):ti,ab
 #5((antimicrobial* or anti‐microbial* or antiseptic* or anti‐septic* or anti‐infect* or antiinfect* or antiviral* or anti‐viral* or alcohol* or ethanol*) near/3 (hand* or wash* or wipe* or gel* or rub* or foam*)):ti,ab
 #6(hand wash* or handrub* or hand gel* or handfoam* or handsaniti*):ti,ab
 #7(rinse‐free* or rinsefree* or rinseless or rinse‐less or non‐rinse*):ti,ab
 #8{or #1‐#7}
 #9[mh "Anti‐infective agents, local"]
 #10[mh "Communicable Diseases"]
 #11[mh "Community‐Acquired Infections"]
 #12[mh Hygiene]
 #13[mh "Infection Control"]
 #14[mh Alcohols]
 #15[mh Ethanol]
 #16{or #9‐#15}
 #17[mh Hands]
 #18#16 and #17
 #19#8 or #18
 #20[mh Child]
 #21[mh "Child, Preschool"]
 #22[mh Adolescent]
 #23[mh Students]
 #24[mh School]
 #25[mh "Schools, Nursery"]
 #26[mh "Child Day Care Centers"]
 #27(preschool* or pre next school* or toddler* or child* or pre next teen* or adolescen* or boy* or girl* or teen* or pre next teen* or young next person* or young next people):ti,ab
 #28(daycare* or day next care* or nurser* or kindergarten* or kinder next garten* or pupil* or student* or school* or college*):ti,ab
 #29[mh Absenteeism]
 #30absentee*:ti,ab
 #31{or #20‐#30}
 #32#19 and #31 in Trials

MEDLINE Ovid

Searched 3 November 2016, 21 February 2019, 19 February 2020.

Lines 34 to 44 of the following MEDLINE strategy are the sensitivity‐maximizing version of the Cochrane Highly Sensitive Search Strategy for identifying randomized trials (Lefebvre 2008).
 1 hand sanitizers/
 2 hand hygiene/
 3 hand disinfection/
 4 (hand$ adj3 (hygiene or wash$ or wipe$ or gel$ or rub$ or foam$ or disinfect$)).tw.
 5 ((antimicrobial$ or anti‐microbial$ or antiseptic$ or anti‐septic$ or anti‐infect$ or antiinfect$ or antiviral$ or anti‐viral$ or alcohol$ or ethanol$) adj5 (hand$ or wash$ or wipe$ or gel$ or rub$ or foam$)).tw.
 6 (sanitis$ or sanitiz$).tw.
 7 (handwash$ or handrub$ or handgel$ or handfoam$ or handsaniti$).tw.
 8 (rinse‐free$ or rinsefree$ or rinseless or rinse‐less or non‐rinse$).tw.
 9 or/1‐8
 10 Anti‐infective agents, local/
 11 exp Communicable Diseases/
 12 Community‐Acquired Infections/
 13 Hygiene/
 14 Infection Control/
 15 Alcohols/
 16 Ethanol/
 17 or/10‐16
 18 Hands/
 19 17 and 18
 20 9 or 19
 21 Child, Preschool/
 22 Child/
 23 Adolescent/
 24 Students/
 25 School/
 26 Schools, Nursery/
 27 Child Day Care Centers/
 28 (preschool$ or pre‐school$ or toddler$ or child$ or pre‐teen$ or adolescen$ or boy$ or girl$ or teen$ or pre‐teen$ or young person$ or young people).tw.
 29 (daycare$ or day care$ or nurser$ or kindergarten$ or kinder‐garten$ or pupil$ or student$ or school$ or college$).tw.
 30 Absenteeism/
 31 absentee$.tw.
 32 or/21‐31
 33 20 and 32
 34 randomized controlled trial.pt.
 35 controlled clinical trial.pt.
 36 randomi#ed.ab.
 37 placebo$.ab.
 38 drug therapy.fs.
 39 randomly.ab.
 40 trial.ab.
 41 groups.ab.
 42 or/34‐41
 43 exp animals/ not humans.sh.
 44 42 not 43
 45 33 and 44

MEDLINE In‐Process & Other Non‐Indexed Citations Ovid

Searched 3 November 2016, 21 February 2019, 19 February 2020.

1 (hand$ adj3 (hygiene or wash$ or wipe$ or gel$ or rub$ or foam$ or disinfect$)).tw.
 2 ((antimicrobial$ or anti‐microbial$ or antiseptic$ or anti‐septic$ or anti‐infect$ or antiinfect$ or antiviral$ or anti‐viral$ or alcohol$ or ethanol$) adj5 (hand$ or wash$ or wipe$ or gel$ or rub$ or foam$)).tw.
 3 (sanitis$ or sanitiz$).tw.
 4 (handwash$ or handrub$ or handgel$ or handfoam$ or handsaniti$).tw.
 5 (rinse‐free$ or rinsefree$ or rinseless or rinse‐less or non‐rinse$).tw.
 6 or/1‐5
 7 (preschool$ or pre‐school$ or toddler$ or child$ or pre‐teen$ or adolescen$ or boy$ or girl$ or teen$ or pre‐teen$ or young person$ or young people).tw.
 8 (daycare$ or day care$ or nurser$ or kindergarten$ or kinder‐garten$ or pupil$ or student$ or school$ or college$).tw. (11226)
 9 absentee$.tw.
 10 or/7‐9
 11 6 and 10

MEDLINE Epub Ahead of Print Ovid

Searched 3 November 2016, 21 February 2019,19 February 2020.

1 (hand$ adj3 (hygiene or wash$ or wipe$ or gel$ or rub$ or foam$ or disinfect$)).tw.
 2 ((antimicrobial$ or anti‐microbial$ or antiseptic$ or anti‐septic$ or anti‐infect$ or antiinfect$ or antiviral$ or anti‐viral$ or alcohol$ or ethanol$) adj5 (hand$ or wash$ or wipe$ or gel$ or rub$ or foam$)).tw.
 3 (sanitis$ or sanitiz$).tw.
 4 (handwash$ or handrub$ or handgel$ or handfoam$ or handsaniti$).tw.
 5 (rinse‐free$ or rinsefree$ or rinseless or rinse‐less or non‐rinse$).tw.
 6 or/1‐5
 7 (preschool$ or pre‐school$ or toddler$ or child$ or pre‐teen$ or adolescen$ or boy$ or girl$ or teen$ or pre‐teen$ or young person$ or young people).tw.
 8 (daycare$ or day care$ or nurser$ or kindergarten$ or kinder‐garten$ or pupil$ or student$ or school$ or college$).tw. (11226)
 9 absentee$.tw.
 10 or/7‐9
 11 6 and 10

Embase Ovid

Searched 3 November 2016, 21 February 2019,19 February 2020.
 1 hand sanitizer/
 2 hand washing/
 3 (hand$ adj3 (hygiene or wash$ or wipe$ or gel$ or rub$ or foam$ or disinfect$)).tw.
 4 ((antimicrobial$ or anti‐microbial$ or antiseptic$ or anti‐septic$ or anti‐infect$ or antiinfect$ or antiviral$ or anti‐viral$ or alcohol$ or ethanol$) adj5 (hand$ or wash$ or wipe$ or gel$ or rub$ or foam$)).tw.
 5 (sanitis$ or sanitiz$).tw.
 6 (handwash$ or handrub$ or handgel$ or handfoam$ or handsaniti$).tw.
 7 (rinse‐free$ or rinsefree$ or rinseless or rinse‐less or non‐rinse$).tw.
 8 or/1‐7
 9 communicable disease/
 10 community acquired infection/
 11 school hygiene/
 12 hygiene/
 13 infection control/
 14 communicable disease control/
 15 antiinfective agent/
 16 alcohol derivative/
 17 alcohol/
 18 or/9‐17
 19 hand/
 20 18 and 19
 21 8 or 20
 22 exp child/
 23 adolescent/
 24 juvenile/
 25 student/
 26 exp school/
 27 day care/
 28 (preschool$ or pre‐school$ or toddler$ or child$ or pre‐teen$ or adolescen$ or boy$ or girl$ or teen$ or pre‐teen$ or young person$ or young people).tw.
 29 (daycare$ or day care$ or nurser$ or kindergarten$ or kinder‐garten$ or pupil$ or student$ or school$ or college$).tw.
 30 absenteeism/
 31 absentee$.tw.
 32 or/22‐31
 33 Randomized controlled trial/
 34 controlled clinical trial/
 35 Single blind procedure/
 36 Double blind procedure/
 37 triple blind procedure/
 38 Crossover procedure/
 39 (crossover or cross‐over).tw.
 40 ((singl$ or doubl$ or tripl$ or trebl$) adj1 (blind$ or mask$)).tw.
 41 Placebo/
 42 placebo.tw.
 43 prospective.tw.
 44 factorial$.tw.
 45 random$.tw.
 46 assign$.ab.
 47 allocat$.tw.
 48 volunteer$.ab.
 49 or/33‐48
 50 21 and 32 and 49

CINAHL Plus EBSCOhost (Cumulative Index to Nursing and Allied Health Literature)

Searched 3 November 2016, 21 February 2019, 19 February 2020.

S1 (MH "Handwashing") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S2 (hand* N3 (hygiene or wash* or wipe* or gel* or rub* or foam* or disinfect*)) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S3 ((antimicrobial* or anti‐microbial* or antiseptic* or anti‐septic* or anti‐infect* or antiinfect* or antiviral* or anti‐viral* or alcohol* or ethanol*) N5 (hand* or wash* or wipe* or gel* or rub* or foam*)) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S4 (sanitis* or sanitiz*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S5 (handwash* or handrub* or handgel* or handfoam* or handsaniti*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S6 (rinse‐free* or rinsefree* or rinseless or rinse‐less or non‐rinse*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S7 S1 OR S2 OR S3 OR S4 OR S5 OR S6 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S8 (MH "Hygiene") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S9 (MH "Infection Control") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S10 (MH "Community‐Acquired Infections+") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S11 (MH "Communicable Diseases") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S12 (MH "Alcohols") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S13 (MH "Ethanol") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S14 S8 OR S9 OR S10 OR S11 OR S12 OR S13 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S15 (MH "Hand") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S16 S14 AND S15 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S17 S7 OR S16 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S18 (MH "Child+") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S19 (MH "Adolescence") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S20 (MH "Students") OR (MH "Students, High School") OR (MH "Students, Middle School") OR (MH "Students, College") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S21 (MH "Schools") OR (MH "Schools, Elementary") OR (MH "Schools, Middle") OR (MH "Schools, Nursery") OR (MH "Schools, Secondary") OR (MH "Schools, Special") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S22 (MH "Child Day Care") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S23 (preschool* or pre‐school* or toddler* or child* or pre‐teen* or adolescen* or boy* or girl* or teen* or pre‐teen* or young person* or young people) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S24 (daycare* or day care* or nurser* or kindergarten* or kinder‐garten* or pupil* or student* or school* or college*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S25 (MH "Absenteeism") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S26 absentee* Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S27 S18 OR S19 OR S20 OR S21 OR S22 OR S23 OR S24 OR S25 OR S26 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S28 S17 AND S27 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S29 (MH "Clinical Trials+") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S30 MH random assignment Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S31 (MH "Meta Analysis") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S32 (MH "Crossover Design") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S33 (MH "Quantitative Studies") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S34 PT randomized controlled trial Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S35 PT Clinical trial Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus y
 S36 (clinical trial*) or (control* N2 trial*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S37 ("follow‐up study" or "follow‐up research") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S38 (prospectiv* study or prospectiv* research) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S39 (evaluat* N2 study or evaluat* N2 research) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S40 (MH "Program Evaluation") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S41 (MH "Treatment Outcomes") Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S42 TI(single N2 mask* or single N2 blind*) OR AB(single N2 mask* or single N2 blind*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S43 TI((doubl* N2 mask*) or (doubl* N2 blind*)) OR AB((doubl* N2 mask*) or (doubl* N2 blind*)) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S44 TI ((tripl* N2 mask*) or (tripl* N2 blind*)) or ((trebl* N2 mask*) or (trebl* N2 blind*)) OR AB((tripl* N2 mask*) or (tripl* N2 blind*)) or ((trebl* N2 mask*) or (trebl* N2 blind*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S45 random* or assign* OR allocat* Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S46 S29 OR S30 OR S31 OR S32 OR S33 OR S34 OR S35 OR S36 OR S37 OR S38 OR S39 OR S40 OR S41 OR S42 OR S43 OR S44 OR S45 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus
 S47 S28 AND S46 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ CINAHL Plus

ERIC EBSCOhost (Education Resources Information Center)

Searched 3 November 2016, 21 February 2019, 19 February 2020.

S1 (hand* N3 (hygiene or wash* or wipe* or gel* or rub* or foam* or disinfect* OR sanitis* or sanitiz*)) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S2 ((antimicrobial* or anti‐microbial* or antiseptic* or anti‐septic* or anti‐infect* or antiinfect* or antiviral* or anti‐viral* or alcohol* or ethanol*) N5 (hand* or wash* or wipe* or gel* or rub* or foam*)) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S3 (handwash* or handrub* or handgel* or handfoam* or handsaniti*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Database ‐ ERIC
 S4 (rinse‐free* or rinsefree* or rinseless or rinse‐less or non‐rinse*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S5 S1 OR S2 OR S3 OR S4 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S6 DE "Late Adolescents" OR DE "Preadolescents" OR DE "Adolescents" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S7 DE "Young Children" OR DE INFANTS OR DE "Preschool Children" OR DE "Toddlers" OR DE "Children" OR DE "Preschool Children" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S8 (preschool* or pre‐school* or toddler* or child* or pre‐teen* or adolescen* or boy* or girl* or teen* or pre‐teen* or young person* or young people) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ AdvancS1 (hand* N3 (hygiene or wash* or wipe* or gel* or rub* or foam* or disinfect* OR sanitis* or sanitiz*)) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S2 ((antimicrobial* or anti‐microbial* or antiseptic* or anti‐septic* or anti‐infect* or antiinfect* or antiviral* or anti‐viral* or alcohol* or ethanol*) N5 (hand* or wash* or wipe* or gel* or rub* or foam*)) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S3 (handwash* or handrub* or handgel* or handfoam* or handsaniti*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S4 (rinse‐free* or rinsefree* or rinseless or rinse‐less or non‐rinse*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S5 S1 OR S2 OR S3 OR S4 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S6 DE "Late Adolescents" OR DE "Preadolescents" OR DE "Adolescents" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S7 DE "Young Children" OR DE INFANTS OR DE "Preschool Children" OR DE "Toddlers" OR DE "Children" OR DE "Preschool Children" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S8 (preschool* or pre‐school* or toddler* or child* or pre‐teen* or adolescen* or boy* or girl* or teen* or pre‐teen* or young person* or young people) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S9 DE "Child Care Centers" OR DE "Early Childhood Education" OR DE "Preschool Education" OR DE "Primary Education" OR DE "Infant Care" OR DE "Preschool Education" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S10 DE "Day Schools" OR DE "Elementary Schools" OR DE "Middle Schools" OR DE "Nursery Schools" OR DE "Secondary Schools" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S11 (daycare* or day care* or nurser* or kindergarten* or kinder‐garten* or pupil* or student* or school* or college*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S12 DE "Attendance" OR DE "Attendance Patterns" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S13 absentee or attendance Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S14 S6 OR S7 OR S8 OR S9 OR S10 OR S11 OR S12 OR S13 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S15 S5 AND S14 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S16 DE "Meta Analysis" OR DE "Evaluation Research" OR DE "Control Groups" OR DE "Experimental Groups" OR DE "Longitudinal Studies" OR DE "Followup Studies" OR DE "Program Effectiveness" OR DE "Program Evaluation" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S17 TI (random* or trial* or PROSPECTIVE* OR longitudinal or BLIND* or CONTROL*) OR AB (random* or trial* or PROSPECTIVE* OR longitudinal or BLIND* or CONTROL* Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S18 S16 OR S17 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S19 S15 AND S18 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S9 DE "Child Care Centers" OR DE "Early Childhood Education" OR DE "Preschool Education" OR DE "Primary Education" OR DE "Infant Care" OR DE "Preschool Education" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S10 DE "Day Schools" OR DE "Elementary Schools" OR DE "Middle Schools" OR DE "Nursery Schools" OR DE "Secondary Schools" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S11 (daycare* or day care* or nurser* or kindergarten* or kinder‐garten* or pupil* or student* or school* or college*) Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S12 DE "Attendance" OR DE "Attendance Patterns" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S13 absentee or attendance Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S14 S6 OR S7 OR S8 OR S9 OR S10 OR S11 OR S12 OR S13 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S15 S5 AND S14 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S16 DE "Meta Analysis" OR DE "Evaluation Research" OR DE "Control Groups" OR DE "Experimental Groups" OR DE "Longitudinal Studies" OR DE "Followup Studies" OR DE "Program Effectiveness" OR DE "Program Evaluation" Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S17 TI (random* or trial* or PROSPECTIVE* OR longitudinal or BLIND* or CONTROL*) OR AB (random* or trial* or PROSPECTIVE* OR longitudinal or BLIND* or CONTROL* Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S18 S16 OR S17 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC
 S19 S15 AND S18 Search modes ‐ Boolean/Phrase Interface ‐ EBSCOhost Research Databases
 Search Screen ‐ Advanced Search
 Database ‐ ERIC

Science Citation Index (SCI); Social Sciences Citation Index (SSCI); Conference Proceedings Citation Index‐ Social Science & Humanities (CPCI‐SSH); Citation Index‐ Science (CPCI‐S). Web of Science (Clarivate)

All Web of Science databases searched 3 November 2016, 22 February 2019, 20 February 2020.

# 12#11 AND #10
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 11TS=(random* or trial* or assign* or control* or group* or placebo* or blind* or prospectiv* or longitudinal* or "meta‐analys*" or "systematic review*")
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 10#9 AND #5
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 9#8 OR #7 OR #6
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 8ts= (absentee* or attendance)
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 7ts=(daycare* or "day‐care*" or nurser* or kindergarten* or "kinder‐garten*" or pupil* or student* or school* or college*)
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 6ts=(preschool* or " pre‐school*" or toddler* or child* or "pre‐teen*" or adolescen* or boy* or girl* or teen* or "young person*" or "young people")
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 5#4 OR #3 OR #2 OR #1
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 4ts=(rinse‐free* or rinsefree* or rinseless or rinse‐less or non‐rinse*)
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 3ts=(handwash* or handrub* or handgel* or handfoam* or handsaniti*)
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 2ts=((antimicrobial* or anti‐microbial* or antiseptic* or anti‐septic* or anti‐infect* or antiinfect* or antiviral* or anti‐viral* or alcohol* or ethanol*) near/5 (hand* or wash* or wipe* or gel* or rub* or foam*))
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years
 # 1ts=(hand* near/3 (hygiene or wash* or wipe* or gel* or rub* or foam* or disinfect* or sanitis* or sanitiz*))
 Indexes=SCI‐EXPANDED, SSCI, CPCI‐S, CPCI‐SSH Timespan=All years

LILACS (Latin American and Caribbean Health Sciences Literature; search.bvsalud.org/portal/?lang=en)

Searched 4 November 2016, 22 February 2019, 20 February 2020.

(mh:((hand hygiene) OR (hand disinfection) OR (hand sanitizers))) OR (ti:((hand* AND (hygiene OR wash* OR wipe* OR gel* OR rub* OR foam* OR disinfect* OR sanitis* OR sanitiz*)))) OR (ab:((hand* AND (hygiene OR wash* OR wipe* OR gel* OR rub* OR foam* OR disinfect* OR sanitis* OR sanitiz*)))) OR (ti:(((antimicrobial* OR anti‐microbial* OR antiseptic* OR anti‐septic* OR anti‐infect* OR antiinfect* OR antiviral* OR anti‐viral* OR alcohol* OR ethanol*) AND (hand* OR wash* OR wipe* OR gel* OR rub* OR foam*)) )) OR (ab:(((antimicrobial* OR anti‐microbial* OR antiseptic* OR anti‐septic* OR anti‐infect* OR antiinfect* OR antiviral* OR anti‐viral* OR alcohol* OR ethanol*) AND (hand* OR wash* OR wipe* OR gel* OR rub* OR foam*)) )) OR (ti:(handwash* OR handrub* OR handgel* OR handfoam* OR handsaniti*)) OR (ab:(handwash* OR handrub* OR handgel* OR handfoam* OR handsaniti*)) OR (ti:(rinse‐free* OR rinsefree* OR rinseless OR rinse‐less OR non‐rinse*)) OR (ab:(rinse‐free* OR rinsefree* OR rinseless OR rinse‐less OR non‐rinse*)) AND (instance:"regional") AND ( db:("LILACS") AND type_of_study:("clinical_trials") AND limit:("humans" OR "child" OR "child, preschool" OR "infant"))

Cochrane Database of Systematic Reviews (CDSR), in the Cochrane Library

Searched 3 November 2016, 22 February 2019, 19 February 2020.

#1[mh "hand sanitizers"]
 #2[mh "hand hygiene"]
 #3[mh "hand disinfection"]
 #4(hand* near/3 (hygiene or wash* or wipe* or gel* or rub* or foam* or disinfect* or sanitis* or sanitiz*)):ti,ab
 #5((antimicrobial* or anti‐microbial* or antiseptic* or anti‐septic* or anti‐infect* or antiinfect* or antiviral* or anti‐viral* or alcohol* or ethanol*) near/5 (hand* or wash* or wipe* or gel* or rub* or foam*)):ti,ab
 #6(handwash* or handrub* or handgel* or handfoam* or handsaniti*):ti,ab
 #7(rinse‐free* or rinsefree* or rinseless or rinse‐less or non‐rinse*):ti,ab
 #8{or #1‐#7}
 #9[mh Child]
 #10[mh "Child, Preschool"]
 #11[mh Adolescent]
 #12[mh Students]
 #13[mh School]
 #14[mh "Schools, Nursery"]
 #15[mh "Child Day Care Centers"]
 #16(preschool* or pre next school* or toddler* or child* or pre next teen* or adolescen* or boy* or girl* or teen* or young next person* or young next people):ti,ab
 #17(daycare* or day next care* or nurser* or kindergarten* or kinder next garten* or pupil* or student* or school* or college*):ti,ab
 #18[mh Absenteeism]
 #19absentee*:ti,ab
 #20{or #9‐#19}
 #21#8 and #20 in Cochrane Reviews (Reviews and Protocols)

Database of Abstracts of Reviews of Effects (DARE), in the Cochrane Library

Searched 3 November 2016. Not searched after 2016 as database no longer mantained.

#1[mh "hand sanitizers"]
 #2[mh "hand hygiene"]
 #3[mh "hand disinfection"]
 #4(hand* near/3 (hygiene or wash* or wipe* or gel* or rub* or foam* or disinfect* or sanitis* or sanitiz*))
 #5((antimicrobial* or anti‐microbial* or antiseptic* or anti‐septic* or anti‐infect* or antiinfect* or antiviral* or anti‐viral* or alcohol* or ethanol*) near/5 (hand* or wash* or wipe* or gel* or rub* or foam*)) 1028
 #6(handwash* or handrub* or handgel* or handfoam* or handsaniti*)
 #7(rinse‐free* or rinsefree* or rinseless or rinse‐less or non‐rinse*)
 #8{or #1‐#7}
 #9[mh "Anti‐infective agents, local"]
 #10[mh "Communicable Diseases"]
 #11[mh "Community‐Acquired Infections"]
 #12[mh Hygiene]
 #13[mh "Infection Control"]
 #14[mh Alcohols]
 #15[mh Ethanol]
 #16{or #9‐#15}
 #17[mh Hands]
 #18#16 and #17
 #19#8 or #18
 #20[mh Child]
 #21[mh "Child, Preschool"]
 #22[mh Adolescent]
 #23[mh Students]
 #24[mh School]
 #25[mh "Schools, Nursery"]
 #26[mh "Child Day Care Centers"]
 #27(preschool* or pre next school* or toddler* or child* or pre next teen* or adolescen* or boy* or girl* or teen* or pre next teen* or young next person* or young next people)
 #28(daycare* or day next care* or nurser* or kindergarten* or kinder next garten* or pupil* or student* or school* or college*)
 #29[mh Absenteeism]
 #30absentee*
 #31{or #20‐#30}
 #32#19 and #31

EPISTEMONIKOS (www.epistemonikos.org)

Used in place of DARE after 2016. Searched 22 February 2019, 19 February 2020.

title:(title:(hand* AND (hygiene OR wash* OR wipe* OR gel* OR rub* OR foam* OR disinfect* OR sanitis* OR sanitiz*)) OR title:(HAND* AND (antimicrobial* OR anti‐microbial* OR antiseptic* OR anti‐septic* OR anti‐infect* OR antiinfect* OR antiviral* OR anti‐viral* OR alcohol* OR ethanol*)) OR title:((rinse‐free* OR rinsefree* OR rinseless OR rinse‐less OR non‐rinse*)) OR title:(handwash* OR handrub* OR handgel* OR handfoam* OR handsaniti*)) AND (title:(ABSENTEE* OR ATENDANCE OR preschool* OR " pre‐school*" OR toddler* OR child* OR "pre‐teen*" OR adolescen* OR boy* OR girl* OR teen* OR "young person*" OR "young people") OR abstract:(ABSENTEE* OR ATENDANCE OR preschool* OR " pre‐school*" OR toddler* OR child* OR "pre‐teen*" OR adolescen* OR boy* OR girl* OR teen* OR "young person*" OR "young people"))

Limited to systematic reviews

Database of Promoting Health Effectiveness Reviews (DoPHER; eppi.ioe.ac.uk/webdatabases4/Intro.aspx?ID=9)

Searched 3 November 2016, 22 February 2019. Search attempted 19 February 2020 but database unresponsive.

Freetext (Title) hand*

ClinicalTrials.gov (www.clinicaltrials.gov/ct2/home)

Searched 21 December 2016, 23 April 2019, 2 March 2020.
 hand sanitizer OR hand sanitiser OR alcohol hand OR ethanol hand OR handrub OR hand anti‐septic OR hand hygiene OR hand rub OR hand foam

World Health Organization International Clinical Trials Registry Platform (WHO ICTRP; apps.who.int/trialsearch/AdvSearch.aspx)

Searched 21 December 2016, 23 April 2019, 2 March 2020
 hand sanitizer OR hand sanitiser OR alcohol hand OR ethanol hand OR handrub OR hand anti‐septic OR hand hygiene OR hand rub OR hand foam

Australian New Zealand Clinical Trials Registry (www.anzctr.org.au)

Searched 21 December 2016, 23 April 2019, 2 March 2020.
 hand sanitizer OR hand sanitiser OR alcohol hand OR ethanol hand

Appendix 2. 'Risk of bias' assessment

1. Random sequence generation (selection bias)

This refers to whether a random process was used to allocate participants to study groups (Higgins 2011a). We will assess included studies to be at low, high or unclear risk of bias on this domain as follows.

1. Low risk of bias: use of the term 'random' and particularly referring to a random number table or computer‐generated random numbers, in addition to the guidance in Table 8.5.d in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011a).

2. High risk of bias: if it is clear that a pseudo‐random or a systematic, non‐random approach was taken, such as allocation by location or date.

3. Unclear risk of bias: insufficient information to make a judgement of high or low risk of bias.

2. Allocation concealment (selection bias)

This refers to whether foreknowledge of forthcoming allocations was prevented (Higgins 2011a). We will assess included studies to be at low, high or unclear risk of bias on this domain as follows.

1. Low risk of bias: when methods such as central allocation or sequentially‐numbered, opaque, sealed envelopes are used. In cluster trials, clusters are often randomised and allocated at the same time, meaning there is a low risk of bias (Higgins 2011a).

2. High risk of bias: when an open, random allocation schedule is used or alternate allocation, or any other method where allocators may potentially foresee assignments (Higgins 2011a).

3. Unclear risk of bias: insufficient information to make a judgement of high or low risk of bias.

3. Blinding of participants and personnel (performance bias)

This can be present when study participants and personnel are aware of the group to which they have been allocated (Higgins 2011a). We will assess included studies to be at low, high or unclear risk of bias on this domain as follows.

1. Low risk of bias: when participants and personnel are unable to determine the treatment group to which they have been allocated.

2. High risk of bias: when participants and personnel are aware of the group to which they have been allocated.

3. Unclear risk of bias: insufficient information to make a judgement of high or low risk of bias.

4. Blinding of outcome assessment (detection bias)

This can be present when outcome assessors are aware of the groups to which participants are allocated (Higgins 2011a). We will assess included studies to be at low, high or unclear risk of bias on this domain as follows.

1. Low risk of bias: when outcome assessors are unable to determine treatment allocation.

2. High risk of bias: when outcome assessors are not blinded to treatment allocation.

3. Unclear risk of bias: insufficient information to make a judgement of high or low risk of bias.

5. Incomplete outcome data (attrition bias)

This can be present when there is incomplete data for each main outcome, including attrition and exclusions (Higgins 2011a). We will assess included studies to be at low, high or unclear risk of bias on this domain as follows.

1. Low risk of bias: no missing outcome data, or the amount of missing data is balanced across groups, or missing data have been imputed appropriately (Higgins 2011a).

2. High risk of bias: missing outcome data, which may be related to the intervention or outcome; or imbalance in missing data across groups.

3. Unclear risk of bias: insufficient information to make a judgement of high or low risk of bias.

6. Selective outcome reporting (reporting bias)

This can be present when there are differences between reported and unreported findings (Higgins 2011a). We will assess included studies to be at low, high or unclear risk of bias on this domain as follows.

1. Low risk of bias: in reviewing the study protocol it is clear that all prespecified outcomes were collected and reported on.

2. High risk of bias: when not all of the study's prespecified outcomes or outcome measurements are reported, or expected outcomes (such as absenteeism) are clearly lacking.

3. Unclear risk of bias: insufficient information to make a judgement of high or low risk of bias.

7. Other bias

This refers to other types of bias that may occur, such as those that can occur with cluster trials (Higgins 2011a). We will assess included studies to be at low, high or unclear risk of bias on this domain as follows.

1. Low risk of bias: when none of the issues reported below are present.

2. High risk of bias: when there is clear imbalance in baseline characteristics between groups, loss of clusters in cluster trials, incorrect analysis (such as not accounting for clustering), or evidence of individuals being preferentially recruited to clusters following the randomization of clusters (Higgins 2011a).

3. Unclear risk of bias: insufficient information to make a judgement of high or low risk of bias.

Appendix 3. Data transformation

Analysis 1.2 Child or student absenteeism due to any illness

Ban 2015 reported the number of ‘person‐months’ taken with sick leave, over the number of months not taken with sick leave, and report the odds ratio (OR 0.61, 95% CI 0.45 to 0.82). This was subsequently converted to a crude rate ratio using the program StatsDirect.

Rinse‐free hand wash: 71 (months lost) / (1869 + 71)

Control: 117 (months lost) / (1873 + 117).

IRR: 0.62 (0.45 to ,0.84).

Pickering 2013 reported narratively that fewer students in intervention schools (11%) self‐reported missing at least 1 day of school (in the week prior) because of illness compared to control schools (20%), and then provided an odds ratio and standard error (OR 0.51, SE = 0.1).

The study authors did provide the number of students assigned to each group. From these values we calculated the number of students in each group, who reported having at least one day absent due to illness.

Intervention: (n = 435), 0.11 x 435 = 47.85 students (48 to nearest whole number)

Control: (n = 469), 0.2 x 469 = 93.8 students (94 to nearest whole number)

This was then converted to determine the relative risk of being absent for at least one day due to illness. These values were then used to calculate a crude rate ratio using the program StatsDirect, which was inputted to RevMan 5 (Review Manager 2014); see below. Calculation of child‐days possible could not be achieved with the data presented.

Rinse‐free hand wash: 48/435

Control: 94/469

IRR: 0.55, (0.38 to 0.78)

Information from the study by Vessey 2007 has come after direct contact was made with the study author. Total absences were reported against child‐days possible for each group. These values were then used to calculate a crude rate ratio using the program StatsDirect (below), which has been inputted to RevMan 5 (Review Manager 2014).

Rinse‐free hand wash: 472 / 14364

Control: 464.8 / 14364

IRR: 0.55 (0.89 to, 1.15)

White 2001 have reported the number of absence episodes against the total child‐days possible. These values were then inputted directly to StatsDirect, where a crude rate ratio could be generated for input to RevMan 5 (Review Manager 2014); (see below).

Rinse‐free hand wash: 96 / 9615

Control: 145 / 9459

IRR: 0.65 (0.49, to 0.84)

Analysis 1.4 Child or pupil absenteeism due to acute respiratory illness

The study by Azor Martinez 2014 collected outcome data for absenteeism due to respiratory illness, but reported these results in a subsequent paper (Azor‐Martinez 2016). These results (reported in the 2016 paper) were reported as the number of days spend absent, compared against the total child‐days possible. This was then converted to a crude rate ratio using Stats Direct (below), which has been inputted to RevMan 5 (Review Manager 2014).

Rinse‐free hand wash: 1014 / 88182

Control: 1720 / 102204

IRR: 0.68 (0.63 to, 0.74)

Azor Martinez 2018 have reported the number of days spent absent, compared against child‐days possible. This was then converted to a crude rate ratio using Stats Direct (below) and inputted directly to RevMan 5 (Review Manager 2014).

Rinse‐free hand wash: 1668 / 51189

Control: 1891 / 44998

Liquid soap: 1627 / 41374

IRR: 0.77 (0.72 to 0.82) (RFHW v Control)

Finally, White 2001 have reported that respiratory‐related absences were decreased by 30.3% (P < 0.01) from the intervention group compared to the control group. This was reported as the number of absence episodes against child‐days possible. This was then converted to a crude rate ratio using Stats Direct (below) and entered into RevMan 5 (Review Manager 2014).

Rinse‐free hand wash : 69 / 9615

Control: 101 / 9459

IRR: 0.67 (0.48, to 0.92)

Analysis 1.5 Child or pupil absenteeism due to gastrointestinal illness

Prazuck 2010 reported that occurrences of gastroenteritis led to 63 absent school days in the rinse‐free hand wash group, compared to 119 days in the control group. The study authors also reported, that the intervention period lasted 17 weeks (of viable data collection). This study was conducted in Olivet, France. The school week in France typically lasts 4.5 days, however, some schools use a 4four‐week day. As no more information was provided by the study author, we have assumed that a four‐day school week was used. These values were calculated (below) and a crude rate ratio could be generated using the program StatsDirect.

Rinse‐free hand wash: 63 school days absent (n = 259)

Control: 119 school days absent (n = 217)

Rinse‐free hand wash: 259 x (17 x 4) = 17612 child‐days possible

Control: 217 x (17 x 4) = 14756 child‐days possible

IRR: 0.44 (0.32, 0.61)

White 2001 reported that gastrointestinal‐related absenteeism decreased by 32.8% (P < 0.001). This has been reported as the number of absence episodes against the total possible days of attendance dichotomously. This was reported as the number of absence episodes against child‐days possible. This was then converted to a crude rate ratio using Stats Direct, which was transformed to log[IRR] and the standard error using RevMan 5 (Review Manager 2014).

Rinse‐free hand wash : 27 / 9615

Control; 44 / 9459

IRR: 0.6 (0.35 to, 0.99)

Analysis 2.1 Child or pupil absenteeism for any reason

Lau 2012 reported the number of days spent absent, compared against child‐days possible. This was then converted to a crude rate ratio using StatsDirect, which was then inputted to RevMan 5 (Review Manager 2014).

Education: 1007/56259

Control: 879/52734

IRR: 1.07 (0.97 to 1.17)

Analysis 2.2 Child or pupil absenteeism due to any illness

Lau 2012 reported that the number of days spent absent (due to any illness) was compared against child‐days possible, and then again converted to a crude rate ratio using StatsDirect before input to RevMan 5 (Review Manager 2014).

Education: 692 / 56259

Control: 655 /52734

IRR: 0.99 (0.89 to, 1.10)

Data and analyses

Comparison 1. Rinse‐free hand wash versus control.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Absenteeism for any reason	2	19605	Incidence Rate Ratio (Fixed, 95% CI)	0.91 [0.82, 1.01]
2 Absenteeism due to any illness	6		Incidence Rate Ratio (Random, 95% CI)	0.82 [0.69, 0.97]
2.1 Preschool age (< 5 years)	2		Incidence Rate Ratio (Random, 95% CI)	0.76 [0.55, 1.07]
2.2 Primary school age (5 ‐ 12 years)	3		Incidence Rate Ratio (Random, 95% CI)	0.92 [0.75, 1.14]
2.3 Mixed age range (2 ‐ 13 years)	1		Incidence Rate Ratio (Random, 95% CI)	0.55 [0.38, 0.80]
3 Adverse skin reactions	3	4365	Risk Ratio (M‐H, Fixed, 95% CI)	1.03 [0.80, 1.32]
3.1 Preschool age (0 ‐ 3 years)	1	673	Risk Ratio (M‐H, Fixed, 95% CI)	2.64 [0.11, 64.59]
3.2 Primary school age (5 ‐ 11 years)	2	3692	Risk Ratio (M‐H, Fixed, 95% CI)	1.02 [0.79, 1.31]
4 Absenteeism due to acute respiratory illness	6	414197	Incidence Rate Ratio (Random, 95% CI)	0.79 [0.68, 0.92]
4.1 Preschool age (0 ‐ 3 years)	1	96187	Incidence Rate Ratio (Random, 95% CI)	0.77 [0.72, 0.82]
4.2 Primary school age (5 ‐ 14 years)	5	318010	Incidence Rate Ratio (Random, 95% CI)	0.79 [0.61, 1.03]
5 Absenteeism due to acute gastrointestinal illness	4	222754	Incidence Rate Ratio (Fixed, 95% CI)	0.79 [0.73, 0.85]

Comparison 2. Rinse‐free hand wash with instruction versus rinse‐free hand wash with no instruction.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Absenteeism for any reason	1		Incidence Rate Ratio (Fixed, 95% CI)	Totals not selected
2 Absenteeism due to any illness	1		Incidence Rate Ratio (Fixed, 95% CI)	Totals not selected

Comparison 3. Rinse‐free hand wash every 120 minutes versus rinse‐free hand wash before lunch.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Absenteeism due to acute respiratory illness	1		Risk Difference (Fixed, 95% CI)	Totals not selected

Comparison 4. Rinse‐free hand wash every 60 minutes versus rinse‐free hand wash every 120 minutes.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Absenteeism due to acute respiratory illness	1		Risk Difference (Fixed, 95% CI)	Totals not selected

Comparison 5. Rinse‐free hand wash every 60 minutes versus rinse‐free hand wash before lunch.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Absenteeism due to acute respiratory illness	1		Risk Difference (Fixed, 95% CI)	Totals not selected

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Azor Martinez 2014.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: a school absenteeism case (episode) was defined as failure of a child to attend school due to an AGE. The research assistant collected the absence sheets weekly that had been sent by the parents, comparing them monthly with the absence register kept by the teachers using an IT program for registering absenteeism from the Department of Education of Andalusia) and telephoned the parents of those children whose cause for absenteeism recorded by the teacher was unclear. Method to classify a gastrointestinal event: a case of AGE was defined as a person with 3 or more loose stools or some vomiting in 24 hours (definition proposed by the International Collaboration on Enteric Disease Burden of Illness Studies). Parents of children who were absent from school due to AGE, recorded AGE symptoms and gave the completed form to the teacher. To assess the accuracy of the symptoms reported by the parents, the research pediatricians reviewed all medical records of the absent pupils due to AGE, using the database of the Department of Health of Andalusia. The final diagnosis was done by the medical researchers on the basis of the symptoms described above and of the revision of the medical history of absent children due of AGE. Method to classify a respiratory illness: respiratory illness was defined by 2 of the following symptoms during a day or by 1 symptom during 2 days (2 consecutive days of cough alone, sneezing alone, or fever alone were not included. (1) runny nose; (2) stuffy or blocked nose or noisy breathing; (3) cough; (4) feeling hot or feverish or having chills; (5) sore throat; or (6) sneezing. To assess the accuracy of the symptoms reported by the parents, the research pediatricians reviewed all medical records of absent pupils because of URI and GI using the database of the Department of Health of Andalusia. The final diagnosis was done by the medical researchers on the basis of the symptoms described above and of the revision of the medical history of absent children due to URI and GI.
Participants	Baseline characteristics Rinse‐free handwashing program Female (%): 303 (48.79%) Male (%): 318 (51.21%) Age distribution: 7.8 av years (SD 2.36) Participants: 621 Control Female (%): 364 (50.5%) Male (%): 356 (49.5%) Age distribution: 8 av years (SD 2.2) Participants: 720 Overall Female (%): 667 (49.73%) Male (%): 674 (50.27%) Age distribution: not specified Participants: 1341 Included criteria: school children aged between 4 and 12 in October 2009, enrolled in the mentioned schools, and whose parents/tutors had signed an informed consent agreement Excluded criteria: school children with chronic illnesses that could affect their likelihood of contracting an infection or the duration of their absence from school Pretreatment: the sociodemographic characteristics of both groups were similar. Although significant differences existed in terms of types of dwelling, this potential bias was controlled for in the multivariate analysis. Time of the year conducted/season: 8 months between October 2009 to May 2010 Country: Almeria Province, Spain Ethnicity: not specified Type of schooling: state primary schools Class sizes: not specified Age distribution: range not specified; however, inclusion criteria states 4‐12 years. Control group = 8 (SD 2.2), experimental group = 7.8 (SD 2.36) Gender distribution: control group = 364 females (50.5%), experimental group = 303 females (48.79%) Language spoken: Spanish
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): 2‐hour handwashing workshop 1 month before study, about "infections most frequently transmitted in schools, how infections are transmitted and prevented, instructions on how and when hands should be washed, use of hand sanitizers and possible side effects." (quote) Concurrent activities: research assistant and teachers sang songs, told stories, put up posters regarding hand hygiene fortnightly Hand hygiene with soap and water instruction: participants were instructed to maintain usual handwashing (soap and water) after going to the toilet and when hands were visibly soiled. Rinse‐free hand washing instruction (particularly regarding frequency of application): use of hand sanitizer after coming into the classroom, before and after lunch, after the break and after physical education lessons, when they went home, after coughing, sneezing or blowing their noses Hand sanitizer availability: hand sanitizer dispensers were installed in the classroom and an information brochure on when and how to wash hands was made available. Application personnel: children. Younger children were supervised by teachers and in some cases it was administered by the teacher. Hand sanitizer name and manufacturer: ALCO ALOE GEL; Americo Govantes Burguete SL Madrid, Spain Hand sanitizer composition (active ingredient): chlorhexidine digluconate at 20% solution; phenoxyethanol 1%; benzalkonium chloride 0.1%; aloe barbadensis 5%; ethyl alcohol 70%; and excipients 100 mL. Alcohol between 65% to 70% degrees, pH = 7–7.5 Cost: not specified Control Education (who delivered the education and the format): none Concurrent activities: none Hand hygiene with soap and water instruction: control group followed usual handwashing without any recommendations or reinforcements on the part of the teacher. Rinse‐free hand washing instruction (particularly regarding frequency of application): none Hand sanitizer availability: none Application personnel: none Hand sanitizer name and manufacturer: none Hand sanitizer composition (active ingredient): none Cost: none
Outcomes	Absenteeism due to gastrointestinal illness Outcome type: dichotomous outcome Reporting: days absent due to GI out of child‐days possible; reported as an IRR Unit of measure: days Direction: lower is better Absenteeism due to respiratory illness (These data have come from Azor‐Martinez 2016) Outcome type: dichotomous outcome Reporting: days absent due to RI out of child‐days possible; transformed to IRR by review authors Unit of measure: days Direction: lower is better Adverse skin reactions Outcome type: dichotomous outcome Reporting: children removed from study due to development of adverse skin reaction Unit of measure: events Direction: lower is better
Identification	Sponsorship source: All phases of this study were supported by a grant from the Department of Health, Andalusia (Pi 0388/2008). The study authors have no other funding or conflicts of interest to disclose. Country: Almeria Province, Spain Setting: 5 state schools in the Almería province Comments: the municipalities were selected because they had already participated in a previous study by the University of Almería regarding water and sustainability. Lead author's name: Ernestina Azor‐Martínez Institution: Distrito Sanitario de Atención Primaria Almería resources: eazorm@yahoo.es Address: Paseo de los Sauces nº2 8ºD, Aguadulce 04720, Almería, Spain
Notes	Comments The other Azor‐Martinez 2016 paper reports on upper respiratory tract infections and is the same trial (review author Zachary Munn on 07 June 2017 at 11:03). This study is the primary study. Additional information included in the other reports has been added to this study (review author Zachary Munn on 10 July 2017 at 21:35).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Judgement comment: low risk of bias as random number table was used for sequence generation.
Allocation concealment (selection bias)	Low risk	Judgement comment: low risk of bias as a random number table was used for sequence generation. In these cases cluster RCTs not normally at risk of bias for allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention, participants and personnel (teachers/research assistant) were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "Parents of children who were absent from school due to AGE, recorded AGE symptoms and gave the completed form to the teacher. One research assistant collected the absence sheets of the participating classes weekly, telephoned the parents of absent children to enquire about the cause of their absence, visited the classrooms and collaborated with the teachers in hand hygiene activities... A case of AGE was defined as a person with 3 or more loose stools or some vomiting, in 24 hours. To assess the accuracy of the symptoms reported by the parents, the research pediatricians reviewed all the medical records of the absent pupils due to AGE, using the database of the department of Health of Andalusia to have medical diagnoses available." Quote: "The final diagnosis was done by the medical researchers on the basis of the symptoms described above and of the revision of the medical history of absent children because of AGE. Permission to revise the medical records and publish results was granted by the ethical review board for clinical trials at the Hospital Torrecardenas, Almería (Spain)." Judgement comment: as the final decision was made by the unblinded researcher, we have rated there to be potential for high risk of detection bias.
Blinding of outcome assessment (detection bias) Adverse skin reactions	Unclear risk	Judgement comment: insufficient information has been provided in text as to how adverse skin reactions were evaluated.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Quote: " Parents of children who were absent from school due to age, recorded age symptoms and gave the completed form to the teacher. One research assistant collected the absence sheets of the participating classes weekly, telephoned the parents of absent children to enquire about the cause of their absence, visited the class‐rooms and collaborated with the teachers in hand hygiene activities. We used the case definition proposed by the international Collaboration on enteric disease Burden of illness Studies. a case of age was defined as a person with 3 or more loose stools or some vomiting, in 24 hours. 35 to assess the accuracy of the symptoms reported by the parents, the research pediatricians reviewed all the medical records of the absent pupils due to age, using the database of the department of Health of Andalusia to have medical diagnoses available. the final diagnosis was done by the medical researchers on the basis of the symptoms described above and of the revision of the medical history of absent children because of age. Permission to revise the medical records and publish results was granted by the ethical review board for clinical trials at the Hospital Torrecardenas, Almería (Spain). In this study, a school absenteeism case (episode) was defined as failure of a child to attend school due to AGE. Common infectious illnesses, such as conjunctivitis and skin infections, were not included." Judgement comment: as the final decision was made by the unblinded researcher, we have rated there to be potential for high risk of detection bias.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: low loss to follow‐up, and balanced across groups for absenteeism due to any cause, suggesting a low risk of bias.
Incomplete outcome data (attrition bias) Absenteeism	Low risk	Judgement comment: low loss to follow‐up, and balanced across groups for absenteeism due to any cause, suggesting a low risk of bias.
Selective reporting (reporting bias)	Low risk	Judgement comment: there appears to be no protocol available; however, looking across the methods and results in all of the associated articles, there appears to be a low risk of bias.
Other bias	High risk	Judgement comment: high risk of bias, as the review team calculated incidence rate ratios without adjusting for ICC of the individual study.

Azor Martinez 2018.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: DCC absenteeism episode was defined as when a child fails to attend a DCC because of an RI. The duration of absenteeism was defined as the number of DCC days missed due to an RI, excluding weekends and holidays. RI‐related absenteeism was reported by parents to the DCC who then relayed this information to the investigator. Method to classify a gastrointestinal event: not specified Method to classify a respiratory illness: respiratory illness was defined as the presence of 2 of the following symptoms during 1 day or the presence of 1 of these symptoms for 2 consecutive days‍: (1) runny nose; (2) stuffy or blocked nose or noisy breathing; (3) cough; (4) feeling hot or feverish or having chills; (5) sore throat; or (6) sneezing. A new RI episode was considered to be the occurrence of an RI after a period of 3 symptom‐free days. RI episodes were reported by parents, who stated the symptoms (above) to the DCC who then relayed this information to the investigator.
Participants	Baseline characteristics Rinse‐free handwashing program Female (%): 149 (43.95%) Male (%): 190 (56.05%) Age distribution: 21.59 (SD 8.21) Participants: 339 analyzed (358 randomized) Control Female (%): 126 (42.28%) Male (%): 172 (57.72%) Age distribution: 20.67 (SD 7.94) Participants: 298 analyzed (315 randomized) Soap and water Female (%): 146 (53.28%) Male (%): 128 (46.72%) Age distribution: 21.10 (SD 7.73) Participants: 274 analyzed (287 randomized) Overall Female (%): 421 (46.21%) Male (%): 490 (53.79%) Age distribution: 0‐3 years Participants: 911 Included criteria: children between 0 and 3 years old, enrolled at the aforementioned DCCs and attending for at least 15 hours per week, whose parents and/or guardians had signed an informed consent document Excluded criteria: children with chronic illnesses or medication that could affect their likelihood of contracting an infection Pretreatment: there were multiple differences between the baseline characteristics of the children in all 3 groups of this study. Those that were found to be significantly different between groups included: age at the start of DCC attendance (P = 0.02); hours per week in DCC (P = 0.05); female sex (P = 0.018); immigrant status (P = 0.001); 13‐valent pneumococcal conjugate vaccine (P < 0.001); number of siblings at home (P = 0.017); father's educational level (P < 0.001); mother's educational level (P = 0.002); father's profession (P = 0.002); mother's profession (P = 0.001); type of dwelling (P < 0.001); number of classrooms per DCC (P = 0.035); number of children per DCC staff (P = 0.029) Time of the year conducted/season: the study duration was 8 months (November 2013–June 2014). Country: Spain Ethnicity: Spanish; however, there were significant differences in the number of children who had immigrant status Type of schooling: childcare centre/day care (infants 0‐3 years) Class sizes: not clearly reported, although children per square meter of space in classroom is reported 3.7 (1.7) (RFHW), 3.1 (1.1) (Control) and 2.8 (1.4) (Soap and Water) Age distribution: 0‐3 years Gender distribution: 421 (46.21%) females; 490 (53.79%) males Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): 1 month before beginning the study (1‐3 October 2013), parents and DCC staff assigned to IGs (HSG and SWG) and the CG attended 1‐hour hand hygiene workshops, which were designed and taught by researchers. The content included education about hand‐washing practices and hand sanitizer use and possible side effects and precautionary measures (only for the HSG). Concurrent activities: The HSG also received a supply of hand sanitizer, and the SWG received liquid soap, to use at home during the study period. During the follow‐up, 3 identical training sessions per DCC were given 1 month apart, the first 3 on RIs and their treatments and the second 3 on fever. These were organized by researchers for the parents or DCC staff of the IGs, or both. Those who were unable to attend training in their own DCC were invited to attend sessions at other centers. The content of the workshops was sent by e‐mail to the IGs. Every 2 weeks, the research assistant and the DCC staff performed the same activities, including stories, songs, and posters in the classrooms and DCCs regarding hand hygiene and infection transmission. Hand hygiene with soap and water instruction: Children, parents, and DCC staff in the IGs were instructed by the researchers to maintain their usual hand‐washing procedures after using the toilet and when their hands were visibly dirty. Both IGs had to follow protocol in the following circumstances: after coming into the classroom; before and after lunch; after playing outside; when they went home; after coughing, sneezing, or blowing their noses; and after diapering. In the HSG and SWG classrooms, hand sanitizer and liquid soap dispensers were installed, respectively, and an informational brochure about when and how to perform hand hygiene was made available, which was also provided to the participating families of both groups. Rinse‐free hand washing instruction (particularly regarding frequency of application): Children, parents, and DCC staff in the IGs were instructed by the researchers to maintain their usual hand‐washing procedures after using the toilet and when their hands were visibly dirty. Both IGs had to follow protocol in the following circumstances: after coming into the classroom; before and after lunch; after playing outside; when they went home; after coughing, sneezing, or blowing their noses; and after diapering. Hand sanitizer availability: In the HSG and SWG classrooms, hand sanitizer and liquid soap dispensers were installed, respectively, and an informational brochure about when and how to perform hand hygiene was made available, which was also provided to the participating families of both groups. The HSG also received a supply of hand sanitizer, and the SWG received liquid soap, to use at home during the study period. Application personnel: The HSG children were supervised by DCC staff and parents when using the hand sanitizer, and in the case of young children, it was administered by DCC staff and parents. Hand sanitizer name and manufacturer: no name or brand provided Hand sanitizer composition (active ingredient): 70% ethyl alcohol (pH = 7.0‐7.5) Cost: N/A Control Education (who delivered the education and the format): 1 month before beginning the study (1‐3 October 2013), parents and DCC staff assigned to IGs (HSGand SWG) and the CG attended 1‐hour hand hygiene workshops, which were designed and taught by researchers. The content included education about hand‐washing practices. Concurrent activities: the CG followed usual hand‐washing procedures. Every 2 weeks, the research assistant and the DCC staff performed the same activities, including stories, songs, and posters in the classrooms and DCCs regarding hand hygiene and infection transmission. Hand hygiene with soap and water instruction: the CG followed usual hand‐washing procedures. Rinse‐free hand washing instruction (particularly regarding frequency of application): N/A Hand sanitizer availability: N/A Application personnel: the CG followed usual hand‐washing procedures. Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): N/A Cost: N/A Soap and water Education (who delivered the education and the format): 1 month before beginning the study (1‐3 October 2013), parents and DCC staff assigned to IGs (HSG and SWG) and the CG attended 1‐hour hand hygiene workshops, which were designed and taught by researchers. The content included education about hand‐washing practices. Concurrent activities: the HSG also received a supply of hand sanitizer, and the SWG received liquid soap, to use at home during the study period. During the follow‐up, 3 identical training sessions per DCC were given 1 month apart, the first 3 on RIs and their treatments and the second 3 on fever. These were organized by researchers for the parents or DCC staff of the IGs, or both. Those who were unable to attend training in their own DCC were invited to attend sessions at other centers. The content of the workshops was sent by e‐mail to the IGs. Every 2 weeks, the research assistant and the DCC staff performed the same activities, including stories, songs, and posters in the classrooms and DCCs regarding hand hygiene and infection transmission. Hand hygiene with soap and water instruction: children, parents, and DCC staff in the IGs were instructed by the researchers to maintain their usual hand‐washing procedures after using the toilet and when their hands were visibly dirty. Both IGs had to follow protocol in the following circumstances: after coming into the classroom; before and after lunch; after playing outside; when they went home; after coughing, sneezing, or blowing their noses; and after diapering. In the HSG and SWG classrooms, hand sanitizer and liquid soap dispensers were installed, respectively, and an informational brochure about when and how to perform hand hygiene was made available, which was also provided to the participating families of both groups. Rinse‐free hand washing instruction (particularly regarding frequency of application): N/A Hand sanitizer availability: N/A Application personnel: not specified Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): The liquid soaps used for hand‐washing in the SWG did not contain specific antibacterial components (pH = 5.5). Cost: N/A
Outcomes	Absenteeism due to respiratory illness Outcome type: dichotomous outcome Reporting: days absent due to RI out of child‐days possible; transformed to IRR by review authors Unit of measure: days Direction: lower is better Adverse skin reactions Outcome type: dichotomous outcome Reporting: children removed from the study due to development of adverse skin reaction Unit of measure: events Direction: lower is better
Identification	Sponsorship source: supported by a grant (PI‐0782/2012) from the Department of Health, Andalusia Country: Spain Setting: DCCs in Almeria, Spain Comments: 25 DCC's were randomly selected from 52 possible DCC's in the state Lead author's name: Ernestina Azor‐Martinez Institution: Distrito Sanitario de Atención Primaria, Almería, Spain Email: eazorm@yahoo.es Address: Distrito Sanitario Atención Primaria Almería, Calle Haza de Acosta S/N, 04009 Almería, Spain
Notes	Comments: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "25 DCCs were randomly selected, DCCs were assigned to either an intervention group (IG) or the control group (CG) by means of computer randomization with a 1:1:1 ratio" Judgement comment: low risk of bias as computer randomization was used for sequence generation
Allocation concealment (selection bias)	Low risk	Quote: "(CG) by means of computer randomization with a 1:1:1 ratio, we used statistical software for the selections" Judgement comment: as the randomization procedure was computer generated there is a low risk of bias. In these cases cluster RCTs not normally a risk of bias for allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "Before starting the study, parents authorized their children’s participation and knew which group" Judgement comment: due to the nature of the intervention, parents, DCC staff and investigators were not blinded to treatment assignment.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention, parents, DCC staff and investigators were not blinded to treatment assignment. As parents were responsible for reporting child illness, absenteeism and adverse reactions, there is a high risk of bias.
Blinding of outcome assessment (detection bias) Adverse skin reactions	High risk	Judgement comment: due to the nature of the intervention, parents, DCC staff and investigators were not blinded to treatment assignment. As parents were responsible for reporting child illness, absenteeism and adverse reactions, there is a high risk of bias.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Judgement comment: due to the nature of the intervention, parents, DCC staff and investigators were not blinded to treatment assignment. As parents were responsible for reporting child illness, absenteeism and adverse reactions, there is a high risk of bias.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: loss to follow‐up was balanced across groups; missing data did not affect analyses (according to authors)
Incomplete outcome data (attrition bias) Absenteeism	Low risk	Judgement comment: loss to follow‐up was balanced across groups; missing data did not affect analyses (according to authors)
Selective reporting (reporting bias)	Low risk	Judgement comment: in the protocol (clinicaltrials.gov/ct2/show/NCT03294772), the authors say they will collect GI outcomes as well; however, this is likely to be published elsewhere (the authors did this with a previous study). We followed up with email to the authors to try to get these data, but they refused to provide it to the review team, as it was currently under peer review.(Barker 2019 [pers comm])
Other bias	High risk	Judgement comment: baseline characteristics were not all even (in terms of family's socioeconomic status), but these were adjusted for in the analysis. Unclear if adjusted for ICC but adjusted for other factors in the analysis. We calculated incidence rate ratios without adjusting for ICC.

Ban 2015.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: a Children’s Daily Sick Leave Calendar was sent to the classroom teachers of both groups, to collect daily data on sick leave (SL), and were filled out by the teachers. Method to classify a gastrointestinal illness: diarrhea was defined as 3 or more bowel movements in 1 day, watery or loose stools, with or without blood in the stool. Abdominal pain was defined as an ache or pain in the stomach lasting for 1 hour or more. All of the symptoms of illness were diagnosed and filled out by the parents or guardians based on the stated definitions. Gastrointestinal illness (GI) was classified as the appearance of diarrheal symptoms or 2 or more of the following symptoms: diarrhea; fever; and abdominal pain. Method to classify a respiratory illness: acute respiratory illness (ARI) was classified as the appearance of 2 or more of the following symptoms: fever, cough and expectoration, runny nose and nasal congestion. Cough and expectoration were defined as 3 or more coughs in a single hour and lasting for 4 or more hours in a single day, with or without expectoration. Runny nose and nasal congestion were defined as a runny nose lasting for 4 or more hours in 1 day, with or without nasal congestion. All of the symptoms of illness were diagnosed and filled out by the parents or guardians based on the stated definitions. Method to assess compliance with interventions: compliance with interventions was assessed every month by way of surveying the consumption of products. If the products provided became empty, the empty bottles could be exchanged for new ones at any time.
Participants	Baseline characteristics Rinse‐free handwashing program Female (%): 70 (36.1%) Male (%): 124 (63.9%) Age distribution: 3.7 (SD = 0.4) Participants: 194 Control Female (%): 80 (40.2%) Male (%): 119 (59.8%) Age distribution: 3.7 (SD = 0.5) Participants: 199 Overall Female (%): 150 (38.2%) Male (%): 243 (61.8%) Age distribution: 3.7 (SD = 0.45) Participants: 393 Included criteria: children (under 5 years old) from kindergartens in central China Excluded criteria: families who had antibacterial products already, and children older than five years of age Pretreatment: significant difference in the proportion of smokers; more families in the control group were smoking households Time of the year conducted/season: the study started in October 2010 and lasted until September 2011. Country: China Ethnicity: Chinese Type of schooling: kindergartens managed by the same committee? (Committee not specified by authors) Class sizes: 5 classes with 221 children (average = 44.2 children per class) in one group and 6 classes with 244 children (average = 40.67 children per class) in the other group Age distribution: 3.7 (SD = 0.45) Gender distribution: 150 (38.2%) females; 243 (61.8%) males Language spoken: Chinese
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): parents or guardians and teachers in the intervention group were instructed, in person, on proper hand hygiene techniques and how to use all of the antibacterial products that were distributed. Concurrent activities: families and kindergartens in the intervention group were provided with antibacterial products for hand hygiene and surface cleaning or disinfection produced by the Whealthfields Lohmann (Guangzhou) Company Ltd. Items distributed included liquid antimicrobial soap for hand washing (active ingredient: 0.2% to 0.3% parachlorometaxylenol); instant hand sanitizer for hand disinfecting (active ingredient: 72% to 75% ethanol); antiseptic germicide (active ingredient: 4.5% to 5.5% parachlorometaxylenol, diluting before use); and bleach (active ingredient: 4.5% to 5.0% sodium hypochlorite, diluting before use) for surface disinfecting. Hand hygiene with soap and water instruction: parents or guardians and teachers in the intervention group were instructed, in person, on proper hand‐hygiene techniques and how to use all of the antibacterial products that were distributed. Children, their family members and teachers were advised to wash their hands daily using liquid antimicrobial soap, especially before eating, after using the bathroom, after blowing their nose, and after outdoor activities. Rinse‐free hand washing instruction (particularly regarding frequency of application): parents or guardians and teachers in the intervention group were instructed, in person, on proper hand‐hygiene techniques and how to use all of the antibacterial products that were distributed. Children, their family members and teachers were advised to wash their hands daily using liquid antimicrobial soap, especially before eating, after using the bathroom, after blowing their nose, and after outdoor activities. Instant hand sanitizer was instructed to be carried daily and used without running water. Hand sanitizer availability: carried daily Application personnel: children under supervision of family or of teachers Hand sanitizer name and manufacturer: hand sanitizer; Whealthfields Lohmann (Guangzhou) Ltd Hand sanitizer composition (active ingredient): instant hand sanitizer for hand disinfecting (active ingredient: 72% to 75% ethanol) Cost: unclear Control Education (who delivered the education and the format): none Concurrent activities: none Hand hygiene with soap and water instruction: none ‐normal practices (not specified by primary author) Rinse‐free hand washing instruction (particularly regarding frequency of application): none ‐ usual care Hand sanitizer availability: none ‐ usual care Application personnel: none ‐ usual care Hand sanitizer name and manufacturer: none ‐ usual care Hand sanitizer composition (active ingredient): none ‐ usual care Cost: no cost
Outcomes	Absenteeism due to any illness Outcome type: dichotomous outcome Reporting: number of "person‐months" (quote)taken with sick leave, reported as an odds ratio; transformed to IRR by review authors Unit of measure: person‐months Direction: lower is better Compliance with the hand hygiene program Outcome type: narrative Reporting: reported narratively Unit of measure: adherence to program Direction: greater compliance is favorable
Identification	Sponsorship source: Institute of Environment Health and Related Product Safety, China CDC: and the Whealthfields Lohmann (Guangzhou) Company Ltd Country: Xintao City, Hubei Province of China Setting: kindergarten and community Comments: none Lead author's name: BAN Hai Qun Institution: Institute of Environment Health and Related Product Safety, Center for Disease Control and Prevention of China Email: zlbxj@263.com Address: Institute of Environment Health and Related Product Safety, Center for Disease Control and Prevention of China, Beijing 100021, China
Notes	Comment: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Judgement comment: it is not clear how the randomization sequence was generated. Also, only two kindergartens participated in this study.
Allocation concealment (selection bias)	High risk	Judgement comment: due to issues with randomization, and there only being two clusters, the risk of bias for allocation concealment is likely to be high.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: blinding was not feasible given the interaction between study participants (schools, students, teachers, etc.) and study leaders
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: insufficient information has been provided in text as to how outcomes were evaluated.
Blinding of outcome assessment (detection bias) Compliance	High risk	Judgement comment: insufficient information has been provided in text as to how outcomes were evaluated.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Judgement comment: insufficient information has been provided in text as to how outcomes were evaluated.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: the losses to follow‐up were measured and no important differences were found between treatment groups in terms of this loss to follow‐up.
Incomplete outcome data (attrition bias) Absenteeism	Low risk	Judgement comment: the losses to follow‐up were measured and no important differences were found between treatment groups in terms of this loss to follow‐up.
Selective reporting (reporting bias)	Low risk	Judgement comment: low risk of bias as the study followed trial protocol
Other bias	High risk	Judgement comment: there were important difference between baseline characteristics of the treatment groups. In addition, the analysis does not seem to have taken clustering into account

Biswas 2019.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: N/A Method to classify a respiratory illness: if a child reported ILI symptoms, the field staff talked to their parent/guardian over phone to confirm symptoms and also measured temperature using a thermometer to determine if the child reported having fever. An ILI episode was defined as measured fever of 38 degrees C, subjective fever and cough. If a child was absent, the field staff followed up by phone to identify the reason for absenteeism and to determine if the child met the ILI case definition.
Participants	Baseline characteristics Rinse‐free handwashing program Female (%): 53* Male (%): 47* Age distribution: N/AParticipants: N = 5077 Control Female (%): 54* Male (%): 46* Age distribution: N/A Participants: N = 5778 Overall Female (%): 53* Male (%): 47* Age distribution: N/A Participants: N = 10,855 Included criteria: included both government and private schools in Bangladesh that had at least 100 enrolled students, and only from grade nursery to grade 5. Excluded criteria: excluded schools that offered education above grade 5 because of differences in student populations, as well as schools that had previously received a hand or respiratory hygiene intervention. Pretreatment: nil Time of the year conducted/season: 2015. 10‐week period between June and September Country: Bangladesh Ethnicity: Bangladesh Type of schooling: nursery (pre‐school) to primary school (grades 1‐5) Class sizes: not specified Age distribution: N/A Gender distribution: as above Language spoken: unclear
Interventions	Intervention characteristics Rinse‐free hand washing program Education: provided hand and respiratory hygiene education, including what to do if their hands were dirty, why students should wash their hands, benefits of washing hands and of using hand sanitizer, and the procedure for washing hands using hand sanitizer. Also taught students to cover their mouth and nose with the upper part of their sleeve while coughing and/or sneezing. Concurrent activities: integrated respiratory hygiene messages into the school’s hygiene curriculum. Following the recommendations from the headmaster/headmistress and members of school management committees, then identified potential teachers in each intervention school who were responsible for dissemination of the intervention messages throughout the intervention period. Trained the selected teachers on intervention messages and behavior change communications over 2 days.These selected teachers communicated these messages with other teachers in their schools. All teachers in intervention schools also received on‐site training on the use of hand sanitizer, as well as on how to prevent respiratory secretions from spreading by covering their mouth and nose by the upper part of their sleeve. In addition, a video clip on respiratory hygiene practice was delivered during behavior change communication sessions to the students. Behavior change materials demonstrating sneezing and coughing into the sleeve and how to use hand sanitizer were distributed and placed around the intervention schools. Classroom teachers conveyed intervention messages three times per week during their regular hygiene education classes. In these health education classes,they emphasized the use of hand sanitizer at key times and encouraged children to practice proper respiratory hygiene behaviors. Classroom teachers also used hand sanitizer in the classroom to encourage students. Hand hygiene with soap and water instruction: N/A Rinse‐free hand washing instruction (particularly regarding frequency of application): All children were encouraged to use the hand sanitizer at five key times during the day: 1) when entering into the classroom; 2) after sneezing, coughing, or blowing their nose; 3) after using the toilet/washroom; 4) before eating any food; and 5) when leaving the school at the end of the day. Hand sanitizer availability: hand sanitizer placed in each classroom and outside toilets at each school Application personnel: students applied their own hand sanitizer. Hand sanitizer name and manufacturer: hand sanitizer that was manufactured by a local pharmaceutical company and was available commercially in Bangladesh (name not specified). Hand sanitizer composition (active ingredient): 63% ethyl alcohol Cost: USD $5.75/L Control Education: control schools did not receive any of the hand sanitizer or hand and respiratory hygiene education intervention during the study period Concurrent activities: N/A Hand hygiene with soap and water instruction: N/A Rinse‐free hand washing instruction (particularly regarding frequency of application): N/A Hand sanitizer availability: N/A Application personnel: N/A Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): N/A Cost: N/A
Outcomes	Absenteeism due to ILI (ILI as surrogate) Outcome type: dichotomous outcome Reporting: episodes of ILI out of student weeks. Reported as an IR per 1,000 student‐weeks Unit of measure: episodes Direction: lower is better Compliance Outcome type: dichotomous Reporting: whether students washed their hands or not, out of total opportunities to wash hands. Also report how much hand sanitizer was used. Unit of measure: event Direction: more is better
Identification	Sponsorship source: This study was funded by the CDC, Atlanta, GA. Country: Bangladesh Setting: nursery and primary schools Comments: N/A Lead author's name: Bishwa Institution: International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh Email: debashish@icddrb.org (primary author) Address: International Centre for Diarrhoeal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sarani, Dhaka 1212, Bangladesh.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Judgement comment: randomly generated 24 global positioning system (GPS) coordinates within a 5‐km radius of the International Center for Diarrheal Disease Research, Bangladesh campus, located in the middle of Dhaka. Field staff visited each GPS point and identified the nearest primary school. We included both government and private schools that had at least 100 enrolled students. We randomly allocated all enrolled schools into one of two groups using a computer‐based random number generator.
Allocation concealment (selection bias)	Low risk	Judgment comment: no specific details provided as to allocation concealment taking place. However, eligibility assessment took place prior to randomization to groups using computer‐based random number generator and this is a cluster RCT design. This suggests a low risk of selection bias.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgment comment: students, teachers and parents of participating schools were aware of the treatment assignment.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgment comment: students, teachers and parents of participating schools as well as study personnel were aware of the treatment assignment.
Blinding of outcome assessment (detection bias) Upper respiratory tract infections	High risk	Judgment comment: ILI used as a surrogate for absenteeism due to respiratory illness. Both the students and teachers who reported ILI to study personnel were aware of treatment assignment and thus unblinded.
Blinding of outcome assessment (detection bias) Compliance	High risk	Judgment comment: both the study personnel observing and the teachers reporting use of RFHW were aware of treatment assignment and were thus unblinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgment comment: low attrition observed for both ILI and compliance
Selective reporting (reporting bias)	Low risk	Judgment comment: appears well reported although could not find protocol
Other bias	Low risk	Judgment comment: no other sources of bias detected.

Correa 2012.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Methods to assess a gastrointestinal event: acute diarrheal disease (ADD) was defined as 3 or more loose stools per day, lasting 24 hours or more. All cases of ADD and ARI were registered and included in the analyses. A new event was defined as an episode occurring 48 hours after a symptom‐free period. Prior to the trial, teachers in both arms received training in case registry. They were instructed to identify signs of ADD or ARI through direct observation, or by asking parents or guardians about signs and symptoms of ADD or ARI as a reason for absenteeism. For each possible case, teachers completed a standard checklist that inquired about the presence, onset, and duration of ADD and ARI signs and symptoms. Because it was not possible to blind teachers to arm assignment, reduction of ascertainment bias was sought by not providing case definitions. Methods to assess a respiratory illness: acute respiratory illness (ARI) was defined as 2 or more of the following symptoms for at least 24 hours, lasting at least 2 days: runny, stuffy, or blocked nose or noisy breathing; cough; fever, hot sensation, or chills; and/or sore throat. All cases of ADD and ARI were registered and included in the analyses. A new event was defined as an episode occurring 48 hours after a symptom‐free period. Prior to the trial, teachers in both arms received training in case registry. They were instructed to identify signs of ADD or ARI through direct observation, or by asking parents or guardians about signs and symptoms of ADD or ARI as a reason for absenteeism. For each possible case, teachers completed a standard checklist that inquired about the presence, onset, and duration of ADD and ARI signs and symptoms. Because it was not possible to blind teachers to arm assignment, reduction of ascertainment bias was sought by not providing case definitions. Methods to assess absenteeism: unclear if absenteeism recorded
Participants	Baseline characteristics Rinse‐free handwashing program Female (%): 343 (43.2%) Male (%): 451 (56.8%) Age distribution: 3.23 (SD 1.0) Participants: 794 Control Female (%): 454 (48.6%) Male (%): 479 (51.4%) Age distribution: 3.23 (SD 1.0) Participants: 933 Overall Female (%): 797 (46.1%) Male (%): 930 (53.9%) Age distribution: 3.23 (SD 1.0) Participants: 1727 Included criteria: eligible childcare centers were either “community homes” (quote) or preschools licensed to care for 12 or more children aged 1–5 years old for 8 hours a day, 5 times per week, and where availability of tap water was limited. Limited tap water availability was defined as "interruptions in water provision lasting 24 hours or more at least once a week, or lasting several hours per day every day" (quote). “Community homes” (quote) were homes of local caregivers trained in basic child‐care, where a maximum of 14 children spend the day in a dedicated room with a bathroom, often without a hand sink. Preschools have 2 to 8 age‐specific classrooms (maximum 32 children) overseen by teachers with formal training. These facilities had 1 or more bathrooms with hand sinks that were often non‐functioning. Excluded criteria: not specified Pretreatment: no significant differences for the site measures, including centre size, water sources, water reliability, functional sink present, protected water storage. Groups were different for gender, insurance status, completion of immunizations and baseline reporting of acute diarrhea. Time of the year conducted/season: February until December 2008 Country: not specified Ethnicity: Colombian Type of schooling: childcare centres Class sizes: not specified Age distribution: 3.23 (SD 1.0) Gender distribution: 797 (46.1%) females; 930 (53.9%) males Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): For centers assigned to the intervention arm, ABH and training on proper use were provided to staff and children. Proper use of ABH was ensured by: (i) a pre‐trial ABH use workshop that followed recommended HH teaching techniques and instructed teachers to add ABH to routine HH and give preference to HSW if hands were visibly soiled; (ii) location of visual reminders on ABH technique in bathrooms and next to dispensers; and (iii) provision of monthly 30‐minute ABH technique refresher workshops (8 per center). Concurrent activities: provision of visual reminders on HH moments and technique, plus a monthly refresher training program Hand hygiene with soap and water instruction: Proper use of ABH was ensured by: (i) a pre‐trial ABH use workshop that followed recommended HH teaching techniques and instructed teachers to add ABH to routine HH and give preference to HSW if hands were visibly soiled; (ii) location of visual reminders on ABH technique in bathrooms and next to dispensers; and (iii) provision of monthly 30‐minute ABH technique refresher workshops (8 per center). Rinse‐free hand washing instruction (particularly regarding frequency of application): proper use of ABH was ensured by: (i) a pre‐trial ABH use workshop that followed recommended HH teaching techniques and instructed teachers to add ABH to routine HH and give preference to HSW if hands were visibly soiled; (ii) location of visual reminders on ABH technique in bathrooms and next to dispensers; and (iii) provision of monthly 30‐minute ABH technique refresher workshops (8 per center). Hand sanitizer availability: one ABH dispenser was installed in each center with fewer than 14 children; in larger centers, one dispenser was installed per classroom, plus an additional one for common areas in those centers with more than 28 children. Dispensers were refilled continuously throughout the trial. Application personnel: teachers and children Hand sanitizer name and manufacturer: Purell®; GOJO Industries, Akron, OH Hand sanitizer composition (active ingredient): 62% ethanol Cost: not specified Control Education (who delivered the education and the format): centers assigned to the control arm were simply told to continue their current practices; placebo was not specified as it would be unethical to use an inactive HH product. Concurrent activities: none Hand hygiene with soap and water instruction: centers assigned to the control arm were simply told to continue their current practices; placebo was not specified as it would be unethical to use an inactive HH product. Rinse‐free hand washing instruction (particularly regarding frequency of application): centers assigned to the control arm were simply told to continue their current practices; placebo was not specified as it would be unethical to use an inactive HH product. Hand sanitizer availability: none Application personnel: none Hand sanitizer name and manufacturer: none Hand sanitizer composition (active ingredient): none Cost: not specified
Outcomes	Adverse skin reactions Outcome type: dichotomous outcome Reporting: reported narratively Unit of measure: events Direction: lower is better Perception of the hand hygiene strategy Outcome type: narrative Reporting: reported narratively Unit of measure: events Direction: favorable perception is better
Identification	Sponsorship source: "Global Development Network (New Delhi, India), Fifth Global Research Project: Promoting Innovative Programs from the Developing World: Towards Realizing the Health MDG’s in Africa and Asia, and the Bill and Melinda Gates Foundation (Seattle, Washington, United States). We acknowledge the support of Fundación Hogar Integral” (FHI) (Bogotá, Colombia), Instituto Colombiano de Bienestar Familiar (ICBF) (Bogotá, Colombia) and Secretaría Distrital de Integración Social (Bogotá, Colombia)....We also wish to recognize Govi Ltda. (Bogotá, Colombia), the local representative of GOJO Industries Inc. (Akron, Ohio, United States of America), which donated the product for the pilot study and provided dispensers and dispenser installations free of charge." (quote). Country: Columbia Setting: urban child care centers Comments: none Lead author's name: Juan C Correa Institution: División de Salud Comunitaria, Fundación Santa Fe de Bogotá, Bogotá, Colombia Email: jccorrea47@gmail.com Address: not specified
Notes	Comments Study design: this study measured rates of illness rather than rates of absenteeism (review author Craig Lockwood on 21 November 2017 at 16:14). Outcomes: available data are limited to hazard ratio's and episodes of absence for diarrhea, or respiratory per child day (review author Craig Lockwood on 11 January 2018 at 16:13). Outcomes: narrative reporting of both AE's and perception of teachers (review author Timothy Barker on 17 July 2019 at 14:41).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "The remaining 42 centers were distributed in 12 groups. Second, using the random function in Microsoft Excel ™ (Microsoft Corp., Redmond, Washington, United States), random numbers (1 or 2) were generated and allotted 1:1 within each group. Finally, a researcher flipped a coin to decide which number would correspond to either arm (heads = 1, intervention; tails = 2, control)." Judgement comment: low risk of bias as computer randomization was used for sequence generation
Allocation concealment (selection bias)	Low risk	Judgement comment: low risk of bias as a random number table was used for sequence generation. In these cases cluster RCTs not normally at risk of bias for allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention teachers were not blinded to treatment assignment. As such, there is a high risk of performance bias.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "Arm assignment, reduction of ascertainment bias was sought by not providing case definitions. Case registry formats were reviewed by the project coordinator (a physician blinded to study arms), who decided if case criteria were met. Doubts were clarified with teachers and, if necessary, children were examined. Case registry was supervised through phone calls and bi‐weekly on‐site visits, during which potential cases (children with runny noses, frequent visits to the toilet) observed by the supervisor were cross‐checked with registries. Teachers received a fixed, modest economic compensation for time spent on case reporting, independent of the number of completed formats." Judgement comment: there is no clear evidence provided in the study that outcome assessors were blinded. As the authors (who were unblinded) were involved across every phase of the trial there is a high risk of detection bias.
Blinding of outcome assessment (detection bias) Perception or satisfaction	High risk	Quote: "Arm assignment, reduction of ascertainment bias was sought by not providing case definitions. Case registry formats were reviewed by the project coordinator (a physician blinded to study arms), who decided if case criteria were met. Doubts were clarified with teachers and, if necessary, children were examined. Case registry was supervised through phone calls and bi‐weekly on‐site visits, during which potential cases (children with runny noses, frequent visits to the toilet) observed by the supervisor were cross‐checked with registries. Teachers received a fixed, modest economic compensation for time spent on case reporting, independent of the number of completed formats." Judgement comment: there is no clear evidence provided in the study that outcome assessors were blinded. As the authors (who were unblinded) were involved across every phase of the trial there is a high risk of detection bias.
Blinding of outcome assessment (detection bias) Compliance	High risk	Quote: "Arm assignment, reduction of ascertainment bias was sought by not providing case definitions. Case registry formats were reviewed by the project coordinator (a physician blinded to study arms), who decided if case criteria were met. Doubts were clarified with teachers and, if necessary, children were examined. Case registry was supervised through phone calls and bi‐weekly on‐site visits, during which potential cases (children with runny noses, frequent visits to the toilet) observed by the supervisor were cross‐checked with registries. Teachers received a fixed, modest economic compensation for time spent on case reporting, independent of the number of completed formats." Judgement comment: there is no clear evidence provided in the study that outcome assessors were blinded. As the authors (who were unblinded) were involved across every phase of the trial there is a high risk of detection bias.
Incomplete outcome data (attrition bias) All outcomes	High risk	Judgement comment: there were large, observed losses to follow‐up. As such, there is a high risk of attrition bias.
Selective reporting (reporting bias)	Low risk	Judgement comment: the trial was registered and it appears like all outcomes have been reported.
Other bias	Low risk	Judgement comment: no other sources of bias were observed.

Gerald 2012.

Methods	Study design: cluster‐randomized controlled trial Study grouping: cross‐over
Participants	Baseline characteristics Rinse‐free handwashing program Female (%): 112 (38.1 %) Male (%): 182 (61.9%) Age distribution: 9.0 (SD = 1.7) Participants: 294 Control Female (%): 99 (42.5%) Male (%): 134 (57.5%) Age distribution: 8.9 (SD = 2.0) Participants: 233 Overall Female (%) 211 (40%) Male (%): 316 (60%) Age distribution: 8.9 (SD = 1.8) Participants: 527 Included criteria: only students with asthma were enrolled as study participants. These students were enrolled by the study coordinator before determination of the school’s sequence assignment. Students were recruited by school nurses and referred to the study coordinator if they (1) attended one of the participating schools, (2) had physician‐diagnosed asthma, and (3) were capable of using a peak flow meter. Excluded criteria: not specified Pretreatment: sequence 1 schools (61.8%) had a higher percentage of white students than sequence 2 schools (39.8%, P = 0.01); otherwise, all measured characteristics were similar across the 2 sequences. Time of the year conducted/season: August 2012 through May 2013, 10 months in total. Country: USA Ethnicity: not specified Type of schooling: county elementary schools Class sizes: not specified Age distribution: 8.9 (SD = 1.8) Gender distribution: 211 (40%) females; 316 (60%) males Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): hand hygiene education was provided to intervention schools at the start of the school year and was reinforced monthly. Hand hygiene education was provided by using the Centers for Disease Control and Prevention’s School Network for Absenteeism Prevention program. Concurrent activities: not specified Hand hygiene with soap and water instruction: regular hand washing with soap and water was promoted after using the restroom and when visible dirt was present on the hands. Rinse‐free hand washing instruction (particularly regarding frequency of application): hand sanitizer use was promoted on arrival in the classroom, before lunch, after using the restroom, and after sneezing or coughing. Hand sanitizer availability: disposable hand sanitizer bottles were provided for use in all restrooms, health rooms, and classrooms. Application personnel: children Hand sanitizer name and manufacturer: GOJO, Akron, OH (name not specified) Hand sanitizer composition (active ingredient): 62% ethyl alcohol foam solution Cost: states no cost Control Education (who delivered the education and the format): the study did not provide usual‐care schools with hand hygiene education or supplies. Concurrent activities: none Hand hygiene with soap and water instruction: usual care practices were of differing quality and frequency Rinse‐free hand washing instruction (particularly regarding frequency of application): none Hand sanitizer availability: the study protocol called for the removal of all hand sanitizer bottles, as well as the hand soap dispensers from sequence 2 schools after the intervention. However, no hand soap refills were provided for these dispensers during the period of usual care. Usual care practices were of differing quality and frequency; most usual care schools included hand sanitizer as a personal item on each student’s supply list. Application personnel: students Hand sanitizer name and manufacturer: not applicable Hand sanitizer composition (active ingredient): not applicable Cost: states no cost
Outcomes	Adverse skin reactions Outcome type: dichotomous outcome Reporting: reported narratively Unit of measure: events Direction: lower is better
Identification	Sponsorship source: supported by a grant from the National Heart, Lung, and Blood Institute (1 R01HL086972). Quick‐relief medication for in‐school use was donated by Schering Plough, which is now owned by Merck and Co, and data system support was provided by BlueCross and BlueShield of Alabama Country: USA Setting: single county school district comprising 31 elementary schools Comments: none Lead author's name: Lynn B Gerald Institution: Division of Health Promotion Sciences, Mel and Enid Zuckerman College of Public Health, Arizona Respiratory Center, University of Arizona, Tucson; and the Division of Community, Environment, and Policy, Mel and Enid Zuckerman College of Public Health, University of Arizona Email: lgerald@email.arizona.edu Address: Division of Health Promotion Sciences, Mel and Enid Zuckerman College of Public Health, Arizona Respiratory Center, University of Arizona, 1295 N Martin Avenue, PO Box 245163, Tucson, AZ, 85724‐5163
Notes	Comments Outcomes: cannot find total possible days for denominator (review author Cindy Stern on 20 February 2018 at 12:31)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Judgement comment: there are no specific details provided by the authors on how the randomization sequence was generated. However, the fact that a statistician was involved in the allocation sequence means we have judged this as low risk of bias.
Allocation concealment (selection bias)	Low risk	Judgement comment: the fact that a statistician was involved in the allocation sequence means we have judged this as a low risk of bias.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention, participants and personnel were not blinded to treatment assignment.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Judgement comment: insufficient information has been provided in text as to how outcomes were evaluated.
Incomplete outcome data (attrition bias) All outcomes	High risk	Judgement comment: There was a high dropout rate and there were important differences between groups in terms of reporting data and missing data. As such, there is a high risk of attrition bias.
Selective reporting (reporting bias)	Low risk	Judgement comment: All outcomes reported as directed in the study protocol
Other bias	High risk	Judgement comment: There was no ICC mentioned, this is significant as there were important differences between clusters. In addition, there was no within‐subject correlation coefficient mentioned for the cross‐over trial. As such, we have judged this to be at high risk of bias.

Lau 2012.

Methods	Study design: controlled, cluster trial Study grouping: parallel group Method to assess absenteeism data: per school policy, data were collected documenting each student absence, as reported by parents. If a reason for absence was not submitted, study personnel called the parents to determine the reason for the absence. Method to assess an illness‐related absence: for the purposes of this study, study personnel classified a respiratory or gastrointestinal illness as an illness‐related absence. Other illnesses or excuses were documented as non‐illness related. Per school policy, however, we were allowed to use class‐level aggregate data on study absences. Method to assess compliance: visual assessment of usage of gel
Participants	Baseline characteristics Rinse‐free handwashing program Gender (female): not specified Gender (male): not specified Age distribution: not specified Participants: not specified Control Gender (female): not specified Gender (male): not specified Age distribution: not specified Participants: not specified Overall Female (%): 520 (53%) Male (%): 461 (47%) Age distribution: not specified Participants: 981 Included criteria: eligible students were enrolled pre‐kindergarten through to the 8th grade (ages 4 –14 years) at Louisa May Alcott Elementary School or Walsh Math and Science Academy in Chicago, Illinois. Excluded criteria: not specified Pretreatment: only reported as between‐school differences, rather than between‐group differences. Time of the year conducted/season: October 2009 to May 2010 during peak flu season. This study also coincided with a H1N1 outbreak, which had resulted in both schools already being provided with alcohol hand gel. No adjustment for effect reported Country: USA Ethnicity: Caucasian, black, Hispanic/Latino and a small number labeled 'other' Type of schooling: public elementary schools Class sizes: differed across both schools, overall average = 49.05 children (SD = 7.5) Age distribution: not specified Gender distribution: 520 (53%) females; 461 (47%) males Language spoken: English
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): in addition to these measures, intervention class‐rooms were given a protocol for hand sanitizer use and received regular instruction in hand hygiene from study personnel. The curriculum included an initial 30‐minute interactive session, which used a black light experiment with glow‐in‐the‐dark “germ” lotion, trivia games (grades 2 through 8), and a demonstration with finger puppets(pre‐kindergarten and kindergarten), as well as three 10‐minute review sessions every two months, focusing on when, how, and why to use hand hygiene Concurrent Activities: posters describing when to use the hand sanitizer were hung up throughout the schools. Study personnel conducted weekly checks to ensure that hand sanitizer and soap were properly stocked and available to all students Hand hygiene with soap and water instruction: children were instructed to use soap and water in lieu of hand sanitizer when hands were visibly dirty. Rinse‐free hand washing instruction (particularly regarding frequency of application): when entering school in the morning, before and after lunch, after coughing or sneezing, after recess, before and after eating in class, after using the gym, after a school field trip, when leaving school for the day Hand sanitizer availability: hand sanitizer and hand washing facilities were made available to students in both the intervention and control group. Mounted near the doorway inside every classroom and near entrances to common areas, including the main office, bathrooms, lunchrooms, computer laboratories,and gymnasiums. (Hand sanitizer was not placed in restrooms to avoid disruption of hand washing with soap and water.) Application personnel: children Hand sanitizer name and manufacturer: specific gel not specified but supplied by Woodward Laboratories Inc (CA, USA). Hand sanitizer composition (active ingredient): 0.13% benzalkonium chloride Cost: not specified Control Education (who delivered the education and the format): no additional education other than instruction to use hand sanitizer and soap and water when hands were visibly dirty. At the conclusion of the study, control classrooms also received the 30‐minute lesson on hand hygiene. Concurrent activities: posters describing when to use the hand sanitizer were hung up throughout the schools. Study personnel conducted weekly checks to ensure that hand sanitizer and soap were properly stocked and available to all students. Hand hygiene with soap and water instruction: children were instructed to use soap and water in lieu of hand sanitizer when hands were visibly dirty. Rinse‐free hand washing instruction (particularly regarding frequency of application): when entering school in the morning; before and after lunch; after coughing or sneezing; after recess; before and after eating in class; after using the gym; after a school field trip; and when leaving school for the day Hand sanitizer availability: hand sanitizer and hand washing facilities were made available to students in both the intervention and control group. They were mounted near the door way inside every classroom and near entrances to common areas, including the main office, bathrooms, lunchrooms, computer laboratories, and gymnasiums. (Hand sanitizer was not placed in restrooms to avoid disruption of hand washing with soap and water.) Application personnel: children Hand sanitizer name and manufacturer: specific gel not specified but supplied by Woodward Laboratories Inc (CA, USA). Hand sanitizer composition (active ingredient): dispensers of alcohol‐free hand sanitizer (active ingredient 0.13% benzalkonium chloride) Cost: unclear
Outcomes	Absenteeism for any reason Outcome type: dichotomous outcome Reporting: days absent for any reason out of child‐days possible; transformed to IRR by review authors Unit of measure: days Direction: lower is better Absenteeism due to any illness Outcome type: dichotomous outcome Reporting: days absent due to any illness out of child‐days possible; transformed to IRR by review authors Unit of measure: days Direction: lower is better
Identification	Sponsorship source: Woodard Laboratories provided the hand gel Country: Chicago, USA Setting: public elementary schools Comments: none Lead author's name: Claudia H Lau Institution: Smith Child Health Research Program, Children's Memorial Hospital Email: RUgupta@childrensmemorial.org Address: Smith Child Health Research Program, Children's Memorial Hospital, 2300 Children's Avenue, Box 157 Chicago, IL, 60614, USA
Notes	Comments: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Judgement comment: sequence generation was systematic but not random. As such, there is a high risk of bias.
Allocation concealment (selection bias)	High risk	Judgement comment: there was insufficient information provided as to the process (if any) of allocation concealment. The author acknowledgements suggest all authors were aware of all phases and steps. As such, we have judged this to be a high risk of bias.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: there was insufficient information provided as to if any blinding took place. The author acknowledgements suggest all authors were aware of all phases and steps. As such, we have judged this to be a high risk of bias.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: there was insufficient information provided as to if any blinding took place. The author acknowledgements suggest all authors were aware of all phases and steps. As such, we have judged this to be a high risk of bias.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Judgement comment: there was insufficient information provided as to if any blinding took place. The author acknowledgements suggest all authors were aware of all phases and steps. As such, we have judged this to be a high risk of bias.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "A total of 981 students were eligible and participated in the study; no students opted out or discontinued participation during the course of the study (Table 1). Data from grades pre‐kindergarten and kindergarten were not used in analyses as a result of inconsistent attendance records, giving a final sample of 773 students" Judgment comment: as the authors excluded every student from pre‐kindergarten and kindergarten, and the population of these groups were largely consistent, differences between attrition of the groups analyzed are likely not to be affected by this discrepancy.
Incomplete outcome data (attrition bias) Absenteeism	Low risk	Quote: "total of 981 students were eligible and participated in the study; no students opted out or discontinued participation during the course of the study (Table 1). Data from grades pre‐kindergarten and kindergarten were not used in analyses as a result of inconsistent attendance records, giving a final sample of 773 students" Judgment comment: as the authors excluded every student from pre‐kindergarten and kindergarten, and the population of these groups were largely consistent, differences between attrition of the groups analyzed are likely not to be affected by this discrepancy.
Selective reporting (reporting bias)	Low risk	Judgement comment: no trial protocol was identified but given that absenteeism is reported in full, we judged this as a low risk of bias
Other bias	High risk	Judgement comment: did not control for clustering. Although the baseline characteristics per school are provided, they are not specified per intervention or control group. As such, we have judged this as a high risk of bias.

Lennell 2008.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: number of absences per 100‐child hours. Child hours is the difference between planned time at the DCC and absence due to infection. Method to classify a gastrointestinal event: did not classify Method to classify a respiratory illness: did not classify
Participants	Baseline characteristics Rinse‐free handwashing program Female %: 48.5% Male %: 51.5% Age distribution: 3.2 (SD = 1.3) Participants: 768 Control Female %: 53.9% Male %: 46.1% Age distribution: 3.1 (SD = 1.4) Participants: 749 Overall Gender (female): not specified Gender (male): not specified Age distribution: not specified Participants: 1517 Included criteria: DCC's located in 10 different counties in south and mid‐Sweden were eligible for inclusion. Approvals from all of the staff and from at least 90% of the parents were required before a DCC could be accepted into the study. Study nurses met with DCC staff and parents during special evening "question and answer" (quote) sessions to provide information one month before the study began. After the approvals had been obtained, all children enrolled in the DCCs were eligible as participants. For an individual child to be included in the study, however, written informed consent had to be sought and obtained from the parent(s). Excluded criteria: not specified Pretreatment: significant difference for age, 3 years (P = 0.09), no other significant differences reported Time of the year conducted/season: November 2004 to June 2005 Country: Sweden Ethnicity: Swedish Type of schooling: day care centre Class sizes: intervention = 16.5 children (minimum = 11, maximum = 21), control = 17 children (minimum = 10, maximum = 24) Age distribution: intervention = 3.2 years (SD = 1.3), control = 3.10 years (SD = 1.4) Gender distribution: intervention = 51.5% boys, control = 46.1% boys Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): verbal and written hand washing instructions for the use of the alcohol‐based hand disinfection were identical for all DCCs. These instructions, along with demonstrations, were provided by the study nurses at the beginning of the study. Concurrent activities: none reported Hand hygiene with soap and water instruction: children and staff were instructed to wash their hands using liquid soap and water, Rinse‐free hand washing instruction (particularly regarding frequency of application): staff and students were instructed to wash their hands with soap and water, then dry with a towel, followed by applying 1 mL to 2 mL of alcohol‐based gel containing 70% ethanol. Timing: after using the toilet; before eating; and when dirty. Hand sanitizer availability: The disinfectant dispensers were placed at the wash basin close to the soap. Application personnel: children and staff applied the disinfectant themselves and, when necessary, younger children received assistance from the staff. Hand sanitizer name and manufacturer: Sterisol AB; Vadstena, Opus Health Care AB, Sweden Hand sanitizer composition (active ingredient): 1 mL to 2 mL alcohol‐based, oily disinfectant gel containing 70% ethanol Cost: the cost for the hand disinfection gel would be less than 10 million SEK (1.7 million US dollars) per year for all 8750 DCCs in Sweden (taken from discussion). Control Education (who delivered the education and the format): children and staff were instructed to wash their hands using liquid soap and water, then dry their hands on a towel. Concurrent activities: none reported Hand hygiene with soap and water instruction: in the control group, the hand hygiene routine was exactly the same except for the use of the disinfectant gel. Rinse‐free hand washing instruction (particularly regarding frequency of application): In the control group, the hand hygiene routine was exactly the same except for the use of the disinfectant gel. Hand sanitizer availability: not specified Application personnel: not specified Hand sanitizer name and manufacturer: not specified Hand sanitizer composition (active ingredient): not specified Cost: not specified
Outcomes	Absenteeism due to any illness Outcome type: dichotomous outcome Reporting: absence episodes over total possible child hours; reported as IRR Unit of measure: rate of absence Direction: dichotomous outcome Adverse skin reactions Outcome type: dichotomous outcome Reporting: reported narratively Unit of measure: events Direction: lower is better Compliance with hand hygiene strategy Outcome type: narrative Reporting: reported narratively Unit of measure: adherence to program Direction: greater compliance is favorable
Identification	Sponsorship source: Swedish Strategic Programme against Antibiotic Resistance (Strama), The Swedish National Board for Health and Welfare, Research Committee of Örebro County Council, and Unit for Research and Development Kronoberg County Council Country: Sweden Setting: community day care centres Comments: none Lead author's name: Anne Lennell Institution: Department of Clinical Microbiology, Unit for Infectious Disease Control, Orebro University Hospital Email: anne.lennell@orebroll.se Address: Department of Clinical Microbiology,Unit for Infectious Disease Control, Orebro University Hospital, Orebro, Sweden
Notes	Comments May duplicate data from the preceding study (review author Craig Lockwood on 08 June 2017 at 09:10) Outcomes: data from regression analysis are not based on the original sample, losses to follow‐up equate to approximately 20 in the intervention group and approximately 50 in the control groups. This study reports episodes of absence, but its not clear if this means one day, or whether one episode can include multiple days (review author Craig Lockwood on 09 February 2018 at 16:54).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Judgement comment: insufficient information provided as to how the sequence was generated. However, the authors state that they matched and then randomized, we therefore believe it to be reasonable to consider this as low risk of bias.
Allocation concealment (selection bias)	Low risk	Judgement comment: as there was a low risk of bias for the 'Random sequence generation' and cluster RCTs are not normally at risk of bias for allocation concealment, we have judged this as a low risk of bias.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the intervention participants and personnel were not blinded to treatment assignment.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: parents and nurses collected all the data during this study. As they were unblinded to treatment assignment there is a high risk of bias.
Blinding of outcome assessment (detection bias) Compliance	High risk	Judgement comment: parents and nurses collected all the data during this study. As they were unblinded to treatment assignment there is a high risk of bias.
Blinding of outcome assessment (detection bias) Absenteeism	High risk
Incomplete outcome data (attrition bias) All outcomes	High risk	Judgment comment: there are issues with dropouts; 17 DCCs dropped out of the control group (more than half) compared to 14 DCCs in the intervention group.
Incomplete outcome data (attrition bias) Absenteeism	High risk	Judgment comment: there are issues with dropouts; 17 DCCs dropped out of the control group (more than half) compared to 14 DCCs in the intervention group.
Selective reporting (reporting bias)	Unclear risk	Judgement comment: there was no protocol identified, no adverse events reported, but common outcomes reported. Insufficient information has been provided to allow for judging as either high or low.
Other bias	High risk	Judgement comment: multiple clusters were lost during the trial

Morton 2004.

Methods	Study design: cluster‐randomized controlled trial Study grouping: cross‐over Method to assess absenteeism data: parental reporting back to the school Method to classify a gastrointestinal event: not described Method to classify a respiratory illness: not described Washout Timeframe: 1 week washout ‐ all hand gel removed from the school
Participants	Baseline characteristics Rinse‐free handwashing program Female (%): 120 (47.4%) Male (%): 133 (52.6%) Age distribution: not specified Participants: 253 Control Female (%): 120 (47.4%) Male (%): 133 (52.6%) Age distribution: not specified Participants: 253 Overall Female (%): 120 (47.4%) Male (%): 133 (52.6%) Age distribution: not specified Participants: 253 Included criteria: children in kindergarten up to the 3rd grade Excluded criteria: parents and guardians of children with known chronic skin conditions, such as eczema, were asked to speak with their child’s physician regarding participation. Any child with a known allergy to any ingredient in the alcohol gel was excluded from participation. Pretreatment: no baseline demographic or socioeconomic data reported Time of the year conducted/season: phase 1 conducted prior to Feburary 2004, phase two commenced in February 2004 Country: USA Ethnicity: not specified Type of schooling: elementary Class sizes: not specified Age distribution: not specified Gender distribution: 120 (47.4%) females; 133 (52.6%) males Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): a nurse taught the 45‐minute Germ Unit to each class prior to the start of the experimental phase. The unit included an overview of good germs, bad germs, how germs make one sick, and how germs are spread.The unit was individualized for each grade level, and children’s books were used as aids for illustrating the concepts. Germ models and the Glo Germ visually demonstrated the vulnerable areas of the hands and how children can spread germs without knowing it (Glo Germ Company, 2019). Glo Germ is a cornstarch‐based product with hand lotion consistency that is luminescent under ultraviolet light. It is a visual method to teach an invisible concept of germs, making it possible for children to visualize areas of the hands that harbor germs and subsequently need more attention (between the fingers and around the fingernails). The sharing of pencils and spreading germs by computer mouses and keyboards were used as examples of common ways that germs are spread. The educational program provided reinforcement of perceived susceptibility and severity within the construct of the Health Belief Model; that is, with the knowledge that was gained and subsequently reinforced, the children were made aware of the potential to contract an infectious illness. The study protocol for hand hygiene was introduced following the germ unit education. The protocol, Healthy Hands Rules was simple and direct. The children referred to the alcohol as "Special Soap" (quote). This was an easy term for them to remember and did not infer any medical meaning. The Healthy Hands Rules helped children adopt positive behaviors related to handwashing. Concurrent activities: healthy hands fridge magnets; daily reminders via PA system; class teachers encouraged gel use and reminded students of the protocol; school nurse visited each class twice Hand hygiene with soap and water instruction: wash hands with regular soap and water if hands have dirt on them prior to using alcohol gel Rinse‐free hand washing instruction (particularly regarding frequency of application): 'healthy hands rules' ‐ use gel on arrival to school, prior to lunch, after the bathroom if soap and water is not available, after rubbing their nose or eyes or if their fingers are in their mouth, if their teacher asks them Hand sanitizer availability: dispensers were mounted near the door at the entrance of each classroom at an age‐appropriate height. Dispensers were not mounted in the bathrooms, so as to discourage using the alcohol gel in place of regular handwashing, and to enable monitoring of those in the experimental groups. Application personnel: children Hand sanitizer name and manufacturer: AlcoSCRUB®; Erie Scientific Company, Portsmouth NH Hand sanitizer composition (active ingredient): 60% ethyl alcohol Cost: not specified Control Education (who delivered the education and the format): for children in the control groups, the school nurse reviewed information previously taught about good personal hygiene practices. All non‐consented children were taught to "hand wash as usual" (quote) during times that the consented children were using the product. Special attention was directed to the non‐consented children to make them feel included in the mission of the study, "Healthy Children are Healthy Learners" (quote). These children were praised for their handwashing efforts and reminded that they served as "role models" (quote) for all students in the school. Concurrent activities: healthy hands fridge magnets Hand hygiene with soap and water instruction: for children in the control groups, the school nurse reviewed information previously taught about good personal hygiene practices. Rinse‐free hand washing instruction (particularly regarding frequency of application): N/A Hand sanitizer availability: N/A Application personnel: N/A Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): N/A Cost: N/A
Outcomes	Absenteeism due to any illness Outcome type: dichotomous outcome Reporting: see 'notes' Unit of measure: days Direction: lower is better Adverse skin reactions Outcome type: dichotomous outcome Reporting: reports that 10 children were dropped from the study due to skin irritation. However, the study authors do not provide information as to whether or not these irritations were a result of the RFHW. Unit of measure: events Direction: lower is better
Identification	Sponsorship source: Maine School District Erie Scientific. Country: USA Setting: primary school (kindergarten to 3rd grade) in New England Comments: none Lead author's name: Jennifer L Morton Institution: Maine School Administrative District Email: not specified Address: not specified
Notes	Comments Outcomes: cross‐over studies can be measured either at the end of the study, or at the end of the first phase (pre‐cross over). I think there may be behavioral issues with the end of study measures, as the intervention group from phase 1 will have learned knowledge and behaviors that impact how they act during phase 2 (post cross‐over). So I'm looking for data at the end of phase 1 (review author Craig Lockwood on 12 January 2018 at 09:50). Outcomes: the study does not report traditional treatment or control groups, only a single, end of study whole of population end point. Being a cross‐over design, the study does not report useful comparative data (review author Craig Lockwood on 12 January 2018 at 09:50). Population: this was a cross‐over trial; hence, baseline characteristics are not aligned to the usual end of trial analysis, all participants had both control and intervention group exposures (review author Craig Lockwood on 09 February 2018 at 17:09). Outcomes: this study has not been synthesized with the other studies. Phase 1 lasted 46 days and phase 2 lasted 47 days. The study reports the percentage of days missed in each group, for each phase of the study (phase 1: intervention = 4%, control = 4%; phase 2: intervention = 2.9%, control = 3.5%). The study authors also report, that for the 253 students that participated in each phase, a total of 804 school days were lost due to illness‐related absenteeism. With all this information, we can calculate the number of days lost to illness‐related absenteeism for each group. (Phase 1 (contribution) = 46/93 (49.46%), phase 2 (contribution) = 47/93 (50.54%). Intervention = ((4 x 0.4946) + (2.9 x 0.5054))/(49.46 + 50.54) = 3.44406%. 0.0344406 x (93 x 253)/2 = 405.176 days absent due to illness. Control = ((4 x 0.4946) + (3.5 x 0.5054))/(49.46 + 50.54) = 3.7473. 0.037473 x (93 x 253)/2 = 440.851 days absent due to illness). However, according to the data presented by the study authors, the total days spent absent should total 804. This is not the case when analyzed by the review team. Due to the incompleteness of the provided data by the primary authors, the large number of assumptions that were made by the review team, this has led to a low certainty in the validity of these results. As such, the data from this study have not been combined with the other study data, and the synthesis of this study has been limited to narrative description only (Review author Timothy Barker on 18 July 2019).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: insufficient information has been provided as to how the sequence was generated.
Allocation concealment (selection bias)	Unclear risk	Judgement comment: insufficient information has been provided as to how allocation was concealed.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention, participants and personnel (teachers/research assistant) were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: insufficient information was provided as to the blinding of outcome assessors, however as participants and personnel (teachers/research assistant) were not blinded there is a high risk of bias.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Judgement comment: insufficient information was provided as to the blinding of outcome assessors, however as participants and personnel (teachers/research assistant) were not blinded there is a high risk of bias.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: loss to follow‐up was low and comparable between groups.
Incomplete outcome data (attrition bias) Absenteeism	Low risk	Judgement comment: loss to follow‐up was low and comparable between groups.
Selective reporting (reporting bias)	Low risk	Judgement comment: cannot find reference to a study protocol, but all likely outcomes have been reported.
Other bias	High risk	Judgement comment: this was a cross‐over trial with an insufficient washout period (1 week). In addition, clustering was not taken into account with the analysis.

Pandejpong 2012.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: reported by family to classroom teachers on templates; template included space to indicate influenza‐like symptoms, and whether a GP had been visited. If sick but no GP visit, symptoms were recorded, but a diagnosis was not Method to classify a gastrointestinal event: study did not include GI events Method to classify a respiratory illness: influenza‐like symptoms. If the child was sick but did not see a doctor, the parents were asked to report any of the following symptoms: runny or stuffy nose; cough; fever or chills; sore throat; headache; diarrhea; and presence of hand, foot, or mouth ulcers. If 2 or more of these symptoms were reported, then the child’s illness was documented as ILI.
Participants	Baseline characteristics Rinse free every 120 Female (%): 192 (42.9%) Male (%): 255 (57.1%) Age distribution: mean = 49.85 months Participants: 447 Rinse free at lunch Gender (female): 205 (38.1%) Gender (male): 335 (61.9%) Age distribution: mean = 51.37 months Participants: 538 Rinse free every 60 minutes Gender (female): 241 (53.3%) Gender (male): 211 (46.7%) Age distribution: mean = 50.68 months Participants: 452 Included criteria: the sole inclusion criterion was parental consent to participate in the study Excluded criteria: history of alcohol hand gel allergy Pretreatment: baseline characteristics of all participants after randomization were similar across the intervention groups (no P values reported). Time of the year conducted/season: the study authors collected data between December 2009 and February 2010, in the peak season for ILI in Thailand Country: Thailand Ethnicity: not specified Type of schooling: kindergarten and pre‐school. In Thailand, kindergartens generally divide children into 4 levels, designated as preschool year (PY) 1 for children aged 2‐3 years, PY 2 for children aged 3‐4 years, PY 3 for children aged 4‐5 years, and PY 4 for children aged 5‐6 years. Class sizes: this school included 1441 children and 68 classrooms. Age distribution: 50.68 months Gender distribution: 801 males, 638 females Language spoken: Thai
Interventions	Intervention characteristics Note this study has 3 arms, 1 with alcohol gel every hour, 1 with alcohol gel every 2 hours, and a third group with alcohol gel once per day before lunch. Rinse‐free hand wash every 120 Education (who delivered the education and the format): not specified Concurrent activities: "We described other risk factors for ILI in a leaflet distributed through the school to each participating family after written informed consent was obtained" (quote). Hand hygiene with soap and water instruction: not specified Rinse‐free hand washing instruction (particularly regarding frequency of application): application of alcohol hand gel every 120 minutes Hand sanitizer availability: the teacher was also charged with the proper storage and refilling of the alcohol hand gel during the study period. Application personnel: the teacher was instructed to assist each child in using 1 pump of alcohol hand gel per disinfection round. Hand sanitizer name and manufacturer: alcohol hand gel from the governmental pharmaceutical organization (not specified) Hand sanitizer composition (active ingredient ‐ %): ethyl alcohol (70%); chlorhexidine gluconate (1%); irgasan 0.3%) Cost: $6.30 per child per 12‐week period (taken from discussion, currency not specified) Rinse‐free hand wash before lunch Education (who delivered the education and the format): not specified Concurrent activities: "We described other risk factors for ILI in a leaflet distributed through the school to each participating family after written informed consent was obtained" (quote). Hand hygiene with soap and water instruction: not specified Rinse‐free hand washing instruction (particularly regarding frequency of application): application of hand gel once before lunch Hand sanitizer availability: the teacher was also charged with the proper storage and refilling of the alcohol hand gel during the study period. Application personnel: the teacher was instructed to assist each child in using 1 pump of alcohol hand gel per disinfection round. Hand sanitizer name and manufacturer: alcohol hand gel from the governmental pharmaceutical organization (not specified) Hand sanitizer composition (active ingredient): (active ingredients: 70% ethyl alcohol; 1% chlorhexidine gluconate; 0.3% irgasan) Cost: not specified Rinse‐free hand wash every 60 minutes Education (who delivered the education and the format): not specified Concurrent activities: "We described other risk factors for ILI in a leaflet distributed through the school to each participating family after written informed consent was obtained" (quote). Hand hygiene with soap and water instruction: not specified Rinse‐free hand washing instruction (particularly regarding frequency of application): application of alcohol hand gel every 60 minutes Hand sanitizer availability: the teacher was also charged with the proper storage and refilling of the alcohol hand gel during the study period. Application personnel: the teacher was instructed to assist each child in using 1 pump of alcohol hand gel per disinfection round. Hand sanitizer name and manufacturer: alcohol hand gel from the governmental pharmaceutical organization (not specified) Hand sanitizer composition (active ingredient ‐ %?): (active ingredients: 70% ethyl alcohol; 1% chlorhexidine gluconate; 0.3% irgasan) Cost: not specified
Outcomes	Absenteeism due to respiratory illness Outcome type: absence rate Reporting: reports the rates of absenteeism for each group, and compares the rate difference between groups Unit of measure: rate difference Direction: fewer is better Adverse skin reactions Outcome type: dichotomous outcome Reporting: reported narratively Unit of measure: events Direction: lower is better Perception of the hand hygiene strategy Outcome type: narrative Reporting: reported narratively Unit of measure: events Direction: favorable perception
Identification	Sponsorship source: This research was supported by a Royal College of Physicians of Thailand research grant. Country: Thailand Setting: kindergarten in suburban Bangkok, Thailand Comments: none Lead author's name: Denla Pandejpong Institution: Department of Medicine, Faculty of Medicine, Siriraj Hospital, Bangkok, Thailand Email: sidpd@mahidol.ac.th Address: Siriraj Hospital, Bangkoknio, Bangkok, 10700, Thailand
Notes	Comments Interventions: There are 3 groups in this study, each of which uses alcohol hand gel, simply at differing frequencies: a) hourly; b) two hourly; and c) daily, prior to lunch (review author Craig Lockwood on 12 February 2018 at 17:
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "We used cluster randomization to assign the school’s classrooms to intervention or control groups, with the classroom as the level of randomization." Judgement comment: insufficient information as to how the clusters were randomized.
Allocation concealment (selection bias)	Unclear risk	Judgement comment: cluster trial, already recruited, unlikely to be issues with allocation concealment. However, as it is unclear what the randomization process was, it has been judged as unclear.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: there was no blinding reported, and there is a high probability of contamination across clusters given that clusters sat within the same school and same age groups
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: insufficient information has been provided as to how outcomes were evaluated, however as there was a high risk of performance bias (above) this has been judged as high.
Blinding of outcome assessment (detection bias) Perception or satisfaction	High risk	Judgement comment: insufficient information has been provided as to how outcomes were evaluated, however as there was a high risk of performance bias (above) this has been judged as high.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Judgement comment: insufficient information has been provided as to how outcomes were evaluated, however as there was a high risk of performance bias (above) this has been judged as high.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: authors have reported that there were no losses to follow‐up.
Incomplete outcome data (attrition bias) Absenteeism	Low risk	Judgement comment: authors have reported that there were no losses to follow‐up.
Selective reporting (reporting bias)	Unclear risk	Judgement comment: we could not find a study protocol for this report. As insufficient information was provided as to how outcomes were evaluated this is judged to have been unclear.
Other bias	Low risk	Judgement comment: no ICC was reported by the study authors, however they do mention using logistic regression to account for the cluster design.

Pickering 2013.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group
Participants	Baseline characteristics Rinse‐free handwashing program Female: not specified Male: not specified Age distribution: not specified Participants: 435 Control Female: not specified Male: not specified Age distribution: not specified Participants: 469 Soap Female: not specified Male: not specified Age distribution: not specified Participants: 460 Overall Female: not specified Male: not specified Age distribution: 2‐13 years Participants: 1364 (does not account for those that consented) Included criteria: schools with more than 100 students were considered eligible for the study to ensure balance of school populations across treatment arms. Excluded criteria: schools that shared latrines with community members were excluded because it would not have been feasible to prevent public use of installed hand‐cleaning stations. Pretreatment: most schools purchased water from piped public taps off site, although one control and one soap school had a municipal water connection on the school premises, which provided intermittent supply. Time of year conducted/season: not specified Country: Nairobi Ethnicity: not specified Type of schooling: not specified Class sizes: not specified Age distribution: not specified Gender distribution: not specified Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): initial teacher training session included a participatory discussion with teachers on germ theory and hand hygiene, demonstration and practice of correct handwashing or sanitizing method, and distribution of a culturally appropriate student hand hygiene promotion kit. Unclear who delivered education Concurrent activities: promotion kit included posters, stickers, a classroom activity book, and a DVD presentation on handwashing along with a promotional song Hand hygiene with soap and water instruction: not described Rinse‐free hand washing instruction (particularly regarding frequency of application): not specified Hand sanitizer availability: 2 automatic dispensers (containing hand sanitizer replenished throughout the study), 1 of which was installed next to the toilets and 1 of which was installed near the eating area Application personnel: students Hand sanitizer name and manufacturer: Purell Sanitizer; GOJO industries Ink, Akron, OH Hand sanitizer composition (active ingredient): not specified Cost: not specified Control Education (who delivered the education and the format): not specified Concurrent activities: not specified Hand hygiene with soap and water instruction: not specified Rinse‐free hand washing instruction (particularly regarding frequency of application): N/A Hand sanitizer availability: N/A Application personnel: students Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): N/A Cost: N/A Soap Education (who delivered the education and the format): initial teacher training session like intervention group.Unclear who delivered education Concurrent activities: UNICEF hand hygiene kits provided Hand hygiene with soap and water instruction: 2, manually‐operated dispensers (containing liquid soap replenished throughout the study), 1 of which was installed next to the toilets and 1 of which was installed near the eating area. Also, received a plastic 60 L water tank with spigot mounted on a metal stand. Rinse‐free hand washing instruction (particularly regarding frequency of application): N/A Hand sanitizer availability: N/A Application personnel: students Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): N/A Cost: not specified
Outcomes	Absenteeism due to any illness Outcome type: dichotomous Reporting: student's self‐reported missing at least one‐day of school; reported by the study authors as an OR and converted to IRR by review authors Unit of measure: day Direction: lower is better Adverse skin reactions Outcome type: dichotomous Reporting: reported narratively Unit of measure: events Direction: lower is better Perception of the hand hygiene strategy Outcome type: narrative Reporting: all (100%) teachers interviewed at sanitizer schools stated that they would prefer provision of sanitizer over provision of soap at their school. The majority (91%) of students at sanitizer schools also stated that they would choose sanitizer to clean their hands over soap and water. One teacher said,“I find it [sanitizer] easy to use than soap...If both were given, then you will find the hand sanitizer being used more than soap and water” (quote). Students at sanitizer schools reported that they perceived cleaning hands with sanitizer to take a shorter time than handwashing with soap and water. When asked, 80% of students said that they disagreed with the statement that sanitizer has an unpleasant odor, and 87% of students disagreed that using sanitizer made their hands feel dry. Unit of measure: answers to surveys and structured interviews Direction: favorable perception is better
Identification	Sponsorship source: this study was funded by the Centers for Disease Control and Prevention—Kenya, Kenya Medical Research Institute, and the Freeman Spogli Institute for International Studies at Stanford University; GOJO Industries provided the alcohol‐based hand sanitizer distributed to schools in this study. Country: Nairobi, Kenya Setting: 6 urban primary schools Comments: none Contact author's name: Pavani K Ram Institution: University at Buffalo, State University of New York Email: pkram@buffalo.edu Address: Room 270, Farber Hall, 3435 MainStreet, Buffalo, NY 1421
Notes	Comments Outcomes: this study does not technically measure the outcomes listed in the review. It measures if students were reported missing at least one day of school in the week prior to being interviewed (pre and post intervention) (review author Cindy Stern on 24 August 2017 at 13:32).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: the authors have used the term 'random' but no mention of how randomization occurred (e.g. a random number table or computer‐generated random numbers)
Allocation concealment (selection bias)	Unclear risk	Judgement comment: the authors do not provide a clear description of the randomization process to enable a judgement of whether concealment occurred.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: participants and personnel (students and field staff/enumerators) were not blinded to treatment assignment.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: students and field staff/enumerators aware of treatment assignment. As outcomes were evaluated by enumerators, there is a high risk of bias.
Blinding of outcome assessment (detection bias) Perception or satisfaction	High risk	Judgement comment: students and field staff/enumerators aware of treatment assignment. As outcomes were evaluated by enumerators, there is a high risk of bias.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Judgement comment: students and field staff/enumerators aware of treatment assignment. As outcomes were evaluated by enumerators, there is a high risk of bias.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Judgement comment: there is Insufficient information provided regarding attrition and loss to follow‐up.
Incomplete outcome data (attrition bias) Absenteeism	Unclear risk	Judgement comment: there is Insufficient information provided regarding attrition and loss to follow‐up.
Selective reporting (reporting bias)	Low risk	Judgement comment: no trial protocol was provided but all outcomes as reported in the methods have been included in the results section.
Other bias	Low risk	Judgement comment: no other sources of bias observed.

Prazuck 2010.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: at the beginning of each study week, a questionnaire was given to the children of both schools (A and B). The children's parents had to fill the form by noting, for each day of the week, the presence or absence of the following items: a list of symptoms associated with gastroenteritis; absence from school; GP consultation; and a working day lost by 1 of the parents. The questionnaires were filled in at home by the parents, completed (if necessary) by the teachers (absences, for example), collected at the end of each week by the teacher of each class, and sent to the investigators who verified sheet count. The investigators completed collection of the missing sheets over the following 2 weeks. Each week, up to 478 sheets were collected and computerized for later analysis. Method to classify a gastrointestinal event: A gastroenteritis occurrence was defined by the declared presence of diarrhea of 3 or more stools per day for at least 2 days and/or vomiting associated with at least 1 of the following symptoms: nausea; fever; or abdominal pain. Each time a declared occurrence was combined with a medical consultation, an investigating doctor telephoned the GP to medically check the diagnosis of gastroenteritis.
Participants	Baseline characteristics Rinse‐free hand washing program Female (%): 119 (45.6%) Male (%): 142 (54.4%) Age distribution: 5‐10 years Participants: 261 Control Female (%): 102 (47%) Male (%): 115 (53%) Age distribution: 5‐10 years Participants: 217 Overall Female (%): 221 (46.2%) Male (%): 257 (53.8%) Age distribution: 5‐10 years Participants: 478 Included criteria: not explicitly reported. Two primary schools were selected in the same town on the basis of (1) comparable socioeconomic population status, and (2) an equal number of school children participating in the study. Prior to the start of the study, parental authorization was obtained for each child involved in the study. Excluded criteria: not specified Pretreatment: no statistically significant difference was evident between the characteristics of the children. Time of the year conducted/season: the study took place over a 21‐week period, 17 of which involved collecting data. This took place from November 2007 (week 46) until the Easter holidays in April 2008 (week 14). Two holiday periods interrupted the data collection: the Christmas holidays between week 6 and 7; and the winter holidays between weeks 11 and 12. This study period was included in the gastroenteritis 2007–2008 epidemic period, which spanned from week 47 of 2007 to week 5 of 2008. Country: France Ethnicicty: not specified Type of schooling: primary school Class sizes: not specified; intervention = 10 classes, control = 8 classes Age distribution: 5‐10 years Gender distribution: intervention school = 142 boys and 119 girls, control school = 115 boys and 102 girls Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): information given to students on how to properly wash their hands with water and soap. Additionally, a demonstration on how to use the device was performed by a physician at the beginning of the study. Correct usage was explained to both children and teachers. Application involved pressing the device to obtain a quantity of solution in the hollow of the hand and then rubbing both hands together, followed by crossing the fingers so as to spread the product evenly over the entire cutaneous surface of both hands. Concurrent activities: none stated Hand hygiene with soap and water instruction: information given on how to properly wash their hand with water and soap (not specified who did this) Rinse‐free hand washing instruction (particularly regarding frequency of application): every child had to use the product systematically each time they entered the classroom: twice in the morning (i.e. first entry in the morning and after the morning recess) and twice in the afternoon (i.e. first entry in the afternoon and after the afternoon break). In addition, the device had to be used after returning from restrooms. Hand sanitizer availability: provided on each table in every classroom, where 1 device served 2 children seated at the same table. Application personnel: correct usage of the product was under the supervision of the teacher of each class. Hand sanitizer name and manufacturer: Aniosgel 85 (300 mL virucidal hydroalcoholic solution (HAS)); Anios Corp, Lille Hellemes, France Hand sanitizer composition (active ingredient): 76% ethyl alcohol (2.5% isopropanol) Cost: not specified Control Education (who delivered the education and the format): prior to the study, each child was given specific information on how to properly wash their hands with soap and water and soap in the restrooms. No additional information was given. Concurrent activities: none stated Hand hygiene with soap and water instruction: prior to the study, each child was given specific information on how to properly wash their hands with soap and water and soap in the restrooms (not specified who gave this). Children had to use shared restrooms, as was customary. The shared restrooms consisted of washbasins and soap in an area shared by the entire school, as well as in the school's corridors, and thus was used by children without teacher supervision. Rinse‐free hand washing instruction (particularly regarding frequency of application): not applicable Hand sanitizer availability: N/A Application personnel: children Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): N/A Cost: not specified
Outcomes	Absenteeism due to gastrointestinal illness Outcome type: dichotomous outcome Reporting: days absent due to GI out of child‐days possible; transformed to IRR by review authors Unit of measure: days Direction: lower is better Adverse skin reactions Outcome type: dichotomous outcome Reporting: reported narratively Unit of measure: events Direction: lower is better Compliance with the hand hygiene program Outcome type: narrative Reporting: reported narratively Unit of measure: adherence to program Direction: greater compliance is favorable
Identification	Sponsorship source: ANIOSLab provided hand sanitizer during the study. Country: France Setting: 2 primary schools in the same town (Olivet, France) Comments: none Lead author's name: Thierry Prazuck Institution: Service des Maladies, Infectieuses et Tropicales, CHR Orléans La Source, Orleans Email: thierry.prazuck@chr‐orleans.fr Address: Service des Maladies, Infectieuses et Tropicales, CHR Orléans La Source, BP6709, 45067 Orleans, Cedex 2, France
Notes	Comments: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: the authors state that School A was randomly selected as the treatment group. However no detail is provided as to how this randomization occurred.
Allocation concealment (selection bias)	Unclear risk	Judgement comment: there was not sufficient information regarding the randomization procedure to make a judgement.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the nature of this intervention blinding was not possible. Parental authorization was required for each student, and therefore teachers, students and study personnel were aware of treatment assignment.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: due to the nature of this intervention blinding was not possible. Parental authorization was required for each student, and therefore teachers, students and study personnel were aware of treatment assignment. As absences were reported by teachers there is a high risk of bias. Despite medical consultation being required to confirm gastroenteritis, a medical consultation was not conducted in every case of absenteeism.
Blinding of outcome assessment (detection bias) Compliance	High risk	Judgement comment: due to the nature of this intervention blinding was not possible. Parental authorization was required for each student, and therefore teachers, students and study personnel were aware of treatment assignment. As absences were reported by teachers there is a high risk of bias.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Judgement comment: due to the nature of this intervention blinding was not possible. Parental authorization was required for each student, and therefore teachers, students and study personnel were aware of treatment assignment. As absences were reported by teachers there is a high risk of bias. Despite medical consultation being required to confirm gastroenteritis, a medical consultation was not conducted in every case of absenteeism.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: no loss to follow‐up was reported. Only 2 children in group A were refused participation.
Incomplete outcome data (attrition bias) Absenteeism	Low risk	Judgement comment: no loss to follow‐up was reported. Only 2 children in group A were refused participation.
Selective reporting (reporting bias)	Unclear risk	Judgement comment: a protocol could not be obtained after searching efforts.
Other bias	High risk	Judgement comment: no ICC mentioned or reported and only two clusters were used. In addition, the review team calculated incidence rate ratios without adjusting for ICC of the individual study.

Priest 2014.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: school liaison research assistants visited all schools weekly and collected absence information from the school’s records for the previous week for all children in the school. When a follow‐up child had been absent and the reason for the absence was recorded as medical, illness, or unknown, the caregiver of the child was telephoned. Contact occurred approximately 9 days after the absence, and the caregiver was asked about the reason for the absence. In cases of illness, further questions were asked about the child’s symptoms and their duration. Method to classify a gastrointestinal event: school liaison research assistants visited all schools weekly and collected absence information from the school’s records for the previous week for all children in the school. When a follow‐up child had been absent and the reason for the absence was recorded as medical, illness, or unknown, the caregiver of the child was telephoned. Method to classify a respiratory illness: an absence episode due to illness that includes at least 2 of the following caregiver‐reported symptoms for 1 day, or 1 of the following symptoms for 2 days (but not fever alone): runny nose; stuffy or blocked nose or noisy breathing; cough; fever; sore throat or sneezing.
Participants	Baseline characteristics Rinse‐free hand washing program Female: not specified Male: not specified Age distribution: not specified Participants: 1301 Control Female: not specified Male: not specified Age distribution: not specified Participants: 1142 Overall Female: not specified Male: not specified Age distribution: not specified Participants: 2443 Included criteria: all schools (i) with at least 100 children in school years one to six (aged 5 to 11 years) enrolled at the school in November 2008; (ii) located within the city boundaries of Christchurch, Dunedin, or Invercargill, in the South Island of New Zealand; (iii) not special schools (e.g. schools for children with deafness or disability); and (iv) either not currently using hand sanitizer products or willing to not use hand sanitizer products for the period of the trial if they were randomized to the control group were eligible to participate in the trial. Children were eligible to participate in the follow‐up group, for whom more detailed information on absences was collected, if they attended a school year 1‐to‐6 class in one of the included schools at the beginning of the second school term in 2009 (the end of April), and their caregivers completed the consent form indicating that they were willing to be telephoned following their child's absences and that they were able to take part in telephone interviews in English. Excluded criteria: Potentially eligible follow‐up children were excluded if a caregiver was an investigator or study personnel of the trial, or if the principal of the school directed the authors to not approach the family. Pretreatment: control schools were less advantaged than intervention schools, but otherwise the groups were well balanced Time of the year conducted/season: 27 April to 25 September 2009 (winter school terms) Country: New Zealand Ethnicity: Maori, Pacific, Asian, European, other and not specified Type of schooling: primary schools Class sizes: not specified Age distribution: 5 to 11 years Gender distribution: not specified Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): 30‐minute, in‐class hand hygiene education session; not clear who provided the education Concurrent activities: also instructed in the use of hand sanitizer Hand hygiene with soap and water instruction: not specified Rinse‐free hand washing instruction (particularly regarding frequency of application): asked to use it after coughing/sneezing, and on the way out of the classroom for morning break and for lunch Hand sanitizer availability: during the school holidays in April 2009, no touch dispensers, which dispensed approximately 0.45 ml of alcohol‐based sanitizer (> 60% ethanol) when hands were placed under an infrared sensor, were fitted in all classrooms in intervention schools. Application personnel: children Hand sanitizer name and manufacturer: not specified; however, a change to the hand sanitizer solution was made in 41 of 396 classrooms, halfway through the trial Hand sanitizer composition (active ingredient): no touch dispensers, which dispensed approximately 0.45 ml of alcohol based sanitizer (60% ethanol) when hands were placed under an infrared sensor. Both brands of sanitizer contained 60% ethanol. Cost: not specified Control Education (who delivered the education and the format): children in the control schools received the same in‐class hand hygiene education sessions as the intervention schools (minus the instructions on classroom hand sanitizer use), to ensure that the children in both study groups were equivalent in their exposure to hand hygiene education prior to the study. Concurrent activities: none Hand hygiene with soap and water instruction: not specified Rinse‐free hand washing instruction (particularly regarding frequency of application): N/A Hand sanitizer availability: N/A Application personnel: children Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): N/A Cost: not specified
Outcomes	Absenteeism for any reason Outcome type: dichotomous outcome Reporting: absence episodes over child‐days possible; reported as IRR Unit of measure: absence episodes Direction: lower is better Adverse due to any illness Outcome type: dichotomous outcome Reporting: absence episodes due to any illness over child‐days possible; reported as IRR Unit of measure: absence episodes Direction: lower is better Adverse skin reactions Outcome type: dichotomous outcome Reporting: children removed from study due to development of adverse skin reaction Unit of measure: events Direction: lower is better Compliance with the hand hygiene program Outcome type: narrative Reporting: reported narratively Unit of measure: adherence to program Direction: greater compliance is favorable
Identification	Sponsorship source: Health Research Council of New Zealand Country: New Zealand Setting: primary schools in South Island, New Zealand Comments: none Lead author's name: Patricia Priest Institution: Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand Email: patricia.priest@otago.ac.nz Address: Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago, 201 Great King Street, Dunedin 9016, New Zealand
Notes	Comments: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Schools were randomly allocated to either the hand sanitizer or control group using restricted randomization. Three strata were defined by geographical area (cities of Christchurch, Dunedin, or Invercargill), and within each stratum schools were randomly allocated with equal probability (1∶1 randomization ratio) to the hand sanitizer or control group (i.e., 34 schools per group). City was chosen as a stratification variable because outbreaks of gastrointestinal illness or flu may be restricted to an area, and could therefore confound the estimated intervention effect if the intervention groups were not equally distributed within cities."
Allocation concealment (selection bias)	Low risk	Quote: "The study statistician (J. E. M.) was provided with only a numeric school code and its area, and randomized schools to “A” or “B” using random numbers generated by Stata/MP version 10.1 for Windows (StataCorp). Independently, and prior to receiving the allocation list, P. P. randomly allocated “A” and “B” to intervention or control. Randomisation of all schools was undertaken at one time, and the randomization list was held by P. P. until analysis was complete."
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention children, school administrative staff, and the school liaison research assistants were not blinded to treatment allocation.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: the telephone interviewers (outcome assessors) were blinded to the group allocation until after the analysis was completed. As school staff were aware of group allocation and these staff members reported on the sanitizer usage rates, there is a high risk of detection bias for this outcome.
Blinding of outcome assessment (detection bias) Adverse skin reactions	Low risk	Judgement comment: the telephone interviewers (outcome assessors) were blinded to the group allocation until after the analysis was completed.
Blinding of outcome assessment (detection bias) Compliance	High risk	Judgement comment: ss school staff were aware of group allocation and these staff members reported on the sanitizer usage rates, there is a high risk of detection bias for this outcome.
Blinding of outcome assessment (detection bias) Absenteeism	Low risk	Judgement comment: the telephone interviewers (outcome assessors) were blinded to the group allocation until after the analysis was completed.
Incomplete outcome data (attrition bias) All outcomes	High risk	Judgement comment: there were a lot of missing data on absenteeism. Among the 2443 follow‐up children there were 5766 absences identified from the school rolls, 5134 of which were recorded as 'medical', 'illness', or 'unknown'. Post‐absence phone calls resulted in establishing an absence reason for 3846 absences (74.9%), of which 2833 were identified as being due to illness (Figure 2). There were 608 absences (13.4%) that should have resulted in a call but did not, 284 in the intervention group and 324 in the control group.
Incomplete outcome data (attrition bias) Absenteeism	High risk	Judgement comment: there were a lot of missing data on absenteeism. Among the 2443 follow‐up children there were 5766 absences identified from the school rolls, 5134 of which were recorded as 'medical', 'illness', or 'unknown'. Post‐absence phone calls resulted in establishing an absence reason for 3846 absences (74.9%), of which 2833 were identified as being due to illness (Figure 2). There were 608 absences (13.4%) that should have resulted in a call but did not, 284 in the intervention group and 324 in the control group.
Selective reporting (reporting bias)	Low risk	Judgement comment: as per table 1 of the paper there were a few minor differences in what was planned and what was collected that resulted in 3 minor deviations ‐ none of which affected the outcomes important to this review.
Other bias	Low risk	Judgement comment: no other sources of bias identified.

Sandora 2008.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: all of the student absences were recorded in the usual fashion by the school employee who normally answers this dedicated telephone line. This employee was blinded to the group assignment of the child. In addition to recording the name of the child and the date of the absence, this individual recorded the reason for the absence on a standardized form, from which the absence was classified as respiratory or gastrointestinal illness related (or not illness related), according to protocol‐specified definitions. Method to classify a gastrointestinal event: a gastrointestinal illness was defined as an acute illness that included 2 watery or much looser‐than‐normal bowel movements and stools over a 24‐hour period or vomiting, or both. Method to classify a respiratory illness: a respiratory illness was defined as an acute illness that included 1 of the following symptoms: runny nose; stuffy or blocked nose; cough; fever or chills; sore throat; or sneezing.
Participants	Baseline characteristics Rinse‐free hand washing program Female (%): 79 (54.1%) Male (%) : 65 (45.9%) Age distribution: not specified Participants: 146 Control Female (%): 74 (53.2%) Male (%): 70 (46.8%) Age distribution: not specified Participants: 139 Overall Female (%): 153 (53.7%) Male (%): 135 (46.3%) Age distribution: not specified Participants: 285 Included criteria: student had to be a member of 1 of the classrooms that were located in one of two buildings in the school Excluded criteria: not specified Pretreatment: baseline demographics were similar in the 2 groups Time of the year conducted/season: March to May 2006 Country: USA Ethnicity: White, Black, other Type of schooling: elementary Class sizes: not specified Age distribution: not specified, students were from 3rd, 4th and 5th grade Gender distribution: 153 (53.7%) females; 135 (46.3%) males Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): study personnel instructed students on proper hand hygiene techniques using the sanitizer. Concurrent activities: in each intervention classroom, teachers were given a container of disinfecting wipes (Clorox Disinfecting Wipes (The Clorox Company, Oakland (CA)); active ingredient, 0.29% quaternary ammonium chloride compound) to disinfect the students’ desks once daily (after lunch). The individual containers of wipes were labeled by assigned classroom. All of the disinfecting wipes containers were placed on a shelf in the classroom. Teachers were instructed by the research team on how to use the wipes properly. Hand hygiene with soap and water instruction: hand hygiene with soap and water occurred in the restroom (because sanitizers were not placed there), and after any contact with potentially infectious secretions (e.g. after exposure to other ill children or shared toys that had been mouthed). Rinse‐free hand washing instruction (particularly regarding frequency of application): students were instructed by study personnel on proper hand hygiene techniques using the sanitizer. Students were asked to use the hand sanitizer before and after lunch, and after use of the restroom (on return to the classroom). Hand sanitizer availability: classroom Application personnel: students Hand sanitizer name and manufacturer: AeroFirst, a non aerosol, alcohol‐based foaming hand sanitizer; Deb Sbs Inc, Stanley, NC, for The Clorox Company Hand sanitizer composition (active ingredient): wipes (active ingredient 0.29% quaternary ammonium chloride compound), gel (70% ethyl alcohol) Cost: not specified Control Education (who delivered the education and the format): not specified Concurrent activities: not specified Hand hygiene with soap and water instruction: the usual baseline cleaning procedures and hand hygiene practices were followed (not described). Rinse‐free hand washing instruction (particularly regarding frequency of application): N/A Hand sanitizer availability: N/A Application personnel: students Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): N/A Cost: not specified
Outcomes	Absenteeism due to respiratory illness Outcome type: dichotomous outcome Reporting: rate of absenteeism; reported as IRR Unit of measure: not specified, presume days absent over child‐days possible Direction: lower is better Adverse due to gastrointestinal illness Outcome type: dichotomous outcome Reporting: rate of absenteeism; reported as IRR Unit of measure: not specified, presume days absent over child‐days possible Direction: lower is better Adverse skin reactions Outcome type: dichotomous outcome Reporting: reported narratively Unit of measure: events Direction: lower is better
Identification	Sponsorship source: "Study funds, hand sanitizer, and disinfecting wipes were provided by The Clorox Company (Oakland, CA). The sponsor did not participate in data analysis or article preparation and did not have approval rights over the publication. We are indebted to Charles P Gerba, PhD, Stephanie A Boone, PhD, and Sonia Frankem at the University of Arizona for processing our specimens. We gratefully acknowledge the students and families who participated in the study and the teachers and administration at the Avon Heritage North and South Elementary Schools. We also thank Sharon Wong of the Clinical Research Program at Children’s Hospital Boston for help with creation of our database". (quote). Country: USA Setting: elementary school Comments: none Lead author's name: Thomas J Sandora Institution: Children’s Hospital Boston Email: Thomas.sandora@childrens.harvard.edu Address: Children’s Hospital Boston, Division of Infectious Diseases, 300 Longwood Ave, Boston, MA 02115
Notes	Comments Outcomes: no adverse skin reactions were reported (review author Craig Lockwood on 13 February 2018 at 12:46).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Judgement comment: stratified, cluster randomization with allocation sequence generated by computer. Teams were assigned by a study investigator on this basis.
Allocation concealment (selection bias)	Unclear risk	Judgement comment: the allocation sequence was generated by computer, and teams were assigned to study groups by a study investigator. However, it is not clear whether the investigators were unaware of the allocation schedule prior to recruitment and selection of groups.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: blinding was not specified; however, due to nature of intervention, it would appear that participants and study investigators were aware of group allocations throughout the project.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Judgement comment: blinding was undertaken for the person collecting data on absences Quote: "the individual recording absences for the study was blinded to group assignment"
Blinding of outcome assessment (detection bias) Absenteeism	Low risk	Judgement comment: blinding was undertaken for the person collecting data on absences Quote: "the individual recording absences for the study was blinded to group assignment"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Judgement comment: no students were lost to follow‐up or discontinued the intervention during the study period.
Incomplete outcome data (attrition bias) Absenteeism	Low risk	Judgement comment: no students were lost to follow‐up or discontinued the intervention during the study period.
Selective reporting (reporting bias)	Low risk	Trial was provided and no deviations were identified.
Other bias	Low risk	No other sources of bias identified.

Snow 2008.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: no details ‐ all that is stated is "absences were to be noted" (quote) Method to classify a gastrointestinal event: not applicable Method to classify a respiratory illness: not applicable
Participants	Baseline characteristics Intervention 1 Female (%): 180 (64.5%) Male (%): 99 (35.5%) Age distribution: not specified Participants: 279 Control Female (%): 254 (51%) Male (%): 244 (49%) Age distribution: not specified Participants: 498 Intervention 2 Female (%): 216 (50%) Male (%): 216 (50%) Age distribution: not specified Participants: 432 Overall Female (%): 650 (53.8%) Male (%): 559 ((46.2%) Age distribution: not specified Participants: 1209 Included criteria: not specified Excluded criteria: not specified Pretreatment: not specified Time of the year conducted/season: not specified Country: Utah, USA Ethnicity: not specified Type of schooling: public elementary Class sizes: not specified Age distribution: grades 1‐6 Gender distribution: Language spoken: not specified
Interventions	Intervention characteristics Intervention 1 Education (who delivered the education and the format): none Concurrent activities: teacher modeling ‐ teacher walked over to the classroom sink and washed his/her hands after giving instruction Hand hygiene with soap and water instruction: verbal cue to action ‐ teacher instructed the students to ‘‘Wash your hands then lineup for lunch’’ (quote) Rinse‐free hand washing instruction (particularly regarding frequency of application): not specified Hand sanitizer availability: not specified Application personnel: students Hand sanitizer name and manufacturer: not specified Hand sanitizer composition (active ingredient): not specified Cost: Control (not specified) Education (who delivered the education and the format): none Concurrent activities: none Hand hygiene with soap and water instruction: instructed by the teacher per school policy to "Wash your hands then line up for lunch." (quote) Rinse‐free hand washing instruction (particularly regarding frequency of application): not specified Hand sanitizer availability: not specified Application personnel: students Hand sanitizer name and manufacturer: not specified Hand sanitizer composition (active ingredient): not specified Cost: not specified Intervention 2 Education (who delivered the education and the format): a guest educator teaching a 30‐minute, grade‐appropriate lesson that introduced what germs are, how germs can make people ill, when to wash hands, how to wash your hands, and when it is appropriate to use alcohol hand sanitizers. Concurrent activities: after the guest educator presented the information,students were given an on‐hands experience using simulated germ lotion to see the effectiveness of their hand washing using soap and water. Hand hygiene with soap and water instruction: verbal cue to action ‐ teacher instructed the students every day following the guest presentation to "Wash your hands and line up for lunch, and remember we don't want germs on our hands." (quote) Rinse‐free hand washing instruction (particularly regarding frequency of application): not described Hand sanitizer availability: not specified Application personnel: students Hand sanitizer name and manufacturer: not specified Hand sanitizer composition (active ingredient): not specified Cost: $63.80 (USD)
Outcomes	Compliance with the hand hygiene program/intervention Outcome type: narrative Reporting: reported narratively that both interventions (1 and 2) increased the use of RFHW as a hand hygiene method among children. However, there are issues with this analysis (see 'Notes'). Unit of measure: adherence to program Direction: greater compliance is favorable
Identification	Sponsorship source: not specified Country: USA Setting: public elementary school Comments: none Lead author's name: Michelle Snow Institution: Weber State University Email: michellesnow@weber.edu Address: 3911 University Circle, Ogden, UT 84408‐3911
Notes	Comments We need data regarding just hand sanitizer though and whether this increased compliance (review author Zachary Munn on 15 June 2017 at 17:58). Outcomes: authors measure hand hygiene compliance. There are no outcome data related to absenteeism or illness (review author Craig Lockwood on 13 February 2018 at 13:28). Interventions: After the observational period, each classroom received intervention 2, due to the remarkable increase in student hand hygiene of those originally assigned to this intervention (review author Cindy Stern on 20 February 2018 at 11:41). Outcomes: no data related to absenteeism (review author Cindy Stern on 20 February 2018 at 11:51). Outcomes: the only useful outcome in this study is the narrative report from the study authors, that both intervention 1 and 2 improved the rate at which alcohol‐based hand rubs (RFHW) was used for hand hygiene in children. However, each group (even control) had some access to RFHW. These outcome data simply inform us that education or demonstrations, or both, improve the use of alcohol‐based hand rubs in children, as recorded by the study authors (review author Timothy Barker on 19 July 2019 at 09:50).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: the authors have stated that classes were randomized but no further information given as to how.
Allocation concealment (selection bias)	Unclear risk	Judgement comment: insufficient information provided regarding the randomization procedure to make a judgement regarding allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention, all participants were aware of the group to which they were assigned.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Judgement comment: there is not enough information to be able to determine whether assessors were blinded or not. The paper only states "classroom absences were to be noted" (quote).
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Judgement comment: insufficient information has been provided as to attrition and losses to follow‐up.
Selective reporting (reporting bias)	Unclear risk	Judgement comment: no study protocol was provided, and insufficient information has been provided in the paper to judge this domain as either low or high risk.
Other bias	Unclear risk	Judgement comment: due to the inadequacy of reporting, we have judged this to also be of unclear risk of bias.

Stebbins 2011.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: absence surveillance was the primary mechanism for identification of illness in all schools. Outreach workers collected a daily census of absent students from each school. Method to classify a gastrointestinal event: N/A Method to classify a respiratory illness: project personnel attempted to contact participating parents or guardians within 36 hours to determine the reason for the absence, and a tiered questionnaire was administered to collect information on symptoms. If the ILI definition was met, consent/assent was sought to conduct a home visit. Within 24 hours of obtaining consent, staff conducted home visits to collect demographic information, symptom data, and laboratory specimens. Two nasal swabs were obtained using test, manufacturer‐approved, sterile Dacron swabs. One swab was used for influenza testing, using the QuickVue Influenza AB test (Quidel Corp, San Diego (CA)). The second nasal swab was delivered on cold pack to the University of Pittsburgh Medical Center Clinical Virology Laboratory, Pittsburgh (PA), for RT‐PCR testing (performed within 48 hours). The RT‐PCR used viral nucleic acid extract (EasyMag; bioMerieux, Durham (NC)) and primer/probe sequences for influenza A, influenza B, and influenza A H1 and H3 subtypes (CDC, Atlanta (GA)). The probes were labeled with 6FAM, CAL Fluor Red 590, or Quasar 670 reporter dyes (Biosearch Technologies, Novato (CA)).
Participants	Baseline characteristics Rinse‐free hand washing program Female (%): not specified Male (%): not specified Age distribution: not specified Participants: 1695 Control Female (%): not specified Male (%): not specified Age distribution: not specified Participants: 1665 Overall Female (%): not specified Male (%): not specified Age distribution: not specified Participants: 3360 Included criteria: all enrolled students who were on the school roster at the beginning and end of the school year were considered eligible for the study. Excluded criteria: none mentioned in paper but study protocol states: "Exclusion Criteria (student): The participant has a medical or mental health condition which in the judgment of the investigator is a barrier to safe participation.The participant is unable to tolerate a swab or capillary finger stick.There is a delay in notification or testing such that symptoms have resolved." (quote) Pretreatment: differences between the intervention and control cohorts were noted with regards to age, race, and participation in school lunch programs Time of the year conducted/season: surveillance of absence and the intervention period were carried out between 1 November 2007 and 24 April 2008. Influenza testing of absent students with ILI was performed only during the influenza season; the start of which was determined to be 7 January 2008, based on input from the Allegheny County Health Department combined with results from regional public health laboratories and surveillance systems. Testing stopped on 17 April 2008, after no positive test results were obtained for 2 weeks, combined with agreement from local and state public health departments that the flu season was over. Country: USA Ethnicity: White (control = 44% intervention = 41%), Black (control = 42%, intervention = 49%), and Other (control = 13%, intervention = 10%) Type of schooling: elementary, Pittsburgh public school district Class sizes: mean class size: control = 17.5 children, intervention = 20.2 children; median class size: control = 19 children, intervention = 21 children Age distribution: Kindergarten age to fifth grade (0‐8 years) Gender distribution: not specified Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): "WHACK the Flu" (quote). The intervention was modified to add or sanitize to the W line to read: (W)ash or sanitize your hands often; (H)ome is where you stay when you are sick; (A)void touching your eyes, nose, and mouth; (C)over your coughs and sneezes; and (K)eep your distance from sick people. Project staff conducted grade‐specific, 45‐minute presentations at intervention schools regarding influenza, 'WHACK the Flu' concepts, and proper hand washing technique and sanitizer use. Prior to implementation, project staff conducted grade‐specific, 45‐minute presentations at intervention schools regarding influenza. At the onset of the influenza season in January 2008, project staff provided refresher training at each intervention school. Homeroom teachers were included in both presentations and were asked to reinforce the message and to monitor proper use of hand sanitizer. Concurrent activities: WHACK program Hand hygiene with soap and water instruction: not specified Rinse‐free hand washing instruction (particularly regarding frequency of application): a goal of 4 uses per day— upon arrival, before and after lunch, and prior to departure—was taught to students. They were also encouraged to wash hands or use additional doses of hand sanitizer, or both, as needed. Homeroom teachers were included in both presentations and were asked to reinforce the message and to monitor proper use of hand sanitizer Hand sanitizer availability: hand sanitizer dispensers were installed in each classroom and all major common areas of intervention schools. Application personnel: children Hand sanitizer name and manufacturer: Purell; GOJO Industries Inc, Akron, OH Hand sanitizer composition (active ingredient): hand sanitizer (62% alcohol‐based) Cost: not specified Control Education (who delivered the education and the format): N/A Concurrent activities: N/A Hand hygiene with soap and water instruction: unclear Rinse‐free hand washing instruction (particularly regarding frequency of application): N/A Hand sanitizer availability: N/A Application personnel: N/A Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): N/A Cost: not specified
Outcomes	Absenteeism for any reason Outcome type: dichotomous outcome Reporting: absence episodes over child‐days possible; reported as IRR Unit of measure: episodes Direction: lower is better Absenteeism due to respiratory illness Outcome type: dichotomous outcome Reporting: absence episodes due to RI out of child‐days possible; reported as IRR Unit of measure: episodes Direction: lower is better Compliance with the hand hygiene program (reported in Stebbins 2010) Outcome type: continuous Reporting: teachers completed a survey, in which they were asked to score varius questions regarding student compliance on a Likert scale from ranging from 1 (almost none do) to 5 (almost all do). Reported as mean Unit of measure: adherence to program Direction: greater compliance is favorable
Identification	Sponsorship source: NIH MIDAS program (1U01‐GM070708) (to DC and DB (study authors)) and Cooperative Agreement (number 5UCI000435–02) from the Centers for Disease Control and Prevention (CDC) Country: USA Setting: Pittsburgh elementary schools Comments: protocol on clinicaltrials.gov (NCT00446628) Lead author's name: Samuel Stebbins Institution: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA Email: stebbins@pitt.edu Address: University of PittsburghGraduate School of Public Health, 130 DeSoto St, Room A733,Pittsburgh, PA 15261
Notes	Comments: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Thirteen Pittsburgh elementary schools expressed interest; the largest 10 were selected and assigned to either intervention or control arms by a constrained randomization algorithm using data from the 2006‐2007 school year. The random allocation to two arms was created by Dr. Cummings and concealed until intervention assignment. Five schools were randomized to each group, balancing covariates that might be associated with the primary outcome while maintaining an unbiased and valid randomization"
Allocation concealment (selection bias)	Low risk	Quote: "The random allocation to two arms was created by Dr. Cummings and concealed until intervention assignment. Five schools were randomized to each group, balancing covariates that might be associated with the primary outcome while maintaining an unbiased and valid randomization"
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention participants were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: absence surveillance was performed by outreach workers and project personnel who contacted families. This indicated that they were aware of treatment assignment, as they knew which schools children attended, and therefore were not blinded.
Blinding of outcome assessment (detection bias) Compliance	Unclear risk	Judgement comment: insufficient information was provided as to blinding relevant to the outcome of compliance.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Judgement comment: absence surveillance done by outreach workers and project personnel who contacted families. This indicated that they were aware of treatment assignment, as they knew which schools children attended, and therefore were not blinded.
Incomplete outcome data (attrition bias) All outcomes	High risk	Judgement comment: large amounts of data unable to be collected and are missing on illness‐related absenteeism due to failed contact with the adult respondent.
Incomplete outcome data (attrition bias) Absenteeism	High risk	Judgement comment: large amounts of data unable to be collected and are missing on illness‐related absenteeism due to failed contact with the adult respondent..
Selective reporting (reporting bias)	Low risk	Judgement comment: the protocol does not clearly outline all primary outcomes but all seem to be noted in the study (absences ‐ due to ILI, total, illness, due to influenza, adoption of behavior/activities). The Protocol also refers to absenteeism from all causes, including illness/URI, illness/ILI, illness/other, and illness/GI, however as this is not the focus of this review, there is a low risk of bias.
Other bias	Low risk	Judgement comment: no other sources of bias identified.

Uhari 1999.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: data about the occurrence of infections among the children were collected in a pre‐designed, symptom diary, which was completed by the parents, who returned them to the CDCCs monthly. The study nurse collected these symptom sheets during her visits and contacted parents who had not returned their child's sheet.The children were monitored while they remained at the same CDCC, and thus the number of children participating in the trial could change daily. The data were calculated as events for the time at risk. Because age is an important confounding variable, the calculations regarding symptoms and episodes of infection were performed separately for children younger and older than 3 years. The official records kept by the city council office for invoicing purposes were used as a secondary database for the number of days on which children were absent because of illness. Method to classify a gastrointestinal event: data about the occurrence of infections among the children were collected in a pre‐designed, symptom diary, which was completed by the parents, who returned them to the CDCCs monthly. The study nurse collected these symptom sheets during her visits and contacted parents who had not returned their child's sheet. Method to classify a respiratory illness: data about the occurrence of infections among the children were collected in a pre‐designed, symptom diary, which was completed by the parents, who returned them to the CDCCs monthly. The study nurse collected these symptom sheets during her visits and contacted parents who had not returned their child's sheet.
Participants	Baseline characteristics Rinse‐free hand washing program Female (%): 396 (50.4%) Male (%): 390 (49.6%) Age distribution: 3.6 (SD = 1.9) Participants: 786 Control Female (%): 362 (49.2%) Gender (male): 374 (50.8%) Age distribution: 3.5 (SD = 1.9) Participants: 736 Overall Female (%): 758 (49.8%) Male (%): 764 (50.2%) Age distribution: 3.45 (SD = 1.9) Participants: 1522 Included criteria: municipal, child day care centres in Oulu Excluded criteria: none Pretreatment: there were no clinically significant differences between the intervention CDCCs and control CDCCs in the ages of the children, their attendance for day care or any other important background information. Time of the year conducted/season: March 1991 to the end of May 1992 ‐ all seasons covered Country: Finland Ethnicity: Finnish (presumably) Type of schooling: child care Class sizes: not specified ‐ only provided total numbers of participants by intervention and control CDCCs Age distribution: intervention: mean = 3.6 years (SD = 1.9), control: mean = 3.5 years (SD = 1.9) Gender distribution: intervention = 390 males, 396 females, control = 374 males, 362 females Language spoken: not explicitly stated but assume Finnish and Swedish
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): 1‐hour lecture to personnel on the spread of infections and the possibilities for preventing them, accompanied by a slide show prepared for this purpose. This was given at the beginning of the trial, repeated by the authors in the middle of the trial at 6 months, and repeated also by the study nurse at least three times during the trial. Concurrent activities: infection prevention program. The infection prevention program consisted of intensified hand‐washing; the use of an alcohol‐based, oily disinfectant; directions on the use of disposable towels, cleaning of the CDCCs and regular washing of the toys, or if that was not possible, circulation of the toys so that they were taken out of use for at least every other week. One healthy adult person always served food and tooth brushing was withdrawn. Attention was paid to diaper‐changing practices and the places where this was done. The personnel were encouraged to take sick leave at first appearance of symptoms (exact procedures and instructions given to the personnel are available on request). They also conducted an inventory of possible control measures. The study nurse visited the CDCCs once every 2 weeks to collect symptom diaries and check whether instructions were being followed. Hand hygiene with soap and water instruction: only says "intensified" (quote) Rinse‐free hand washing instruction (particularly regarding frequency of application): not clearly stated Hand sanitizer availability: not specified Application personnel: children and staff Hand sanitizer name and manufacturer: not specified Hand sanitizer composition (active ingredient): alcohol‐based oily disinfectant (no active ingredient specified) Cost: not specified Control Education (who delivered the education and the format): not specified Concurrent activities: the control CDCCs were visited with the same frequency, but no instructions were given on the prevention of infections. Hand hygiene with soap and water instruction: not specified Rinse‐free hand washing instruction (particularly regarding frequency of application): N/A Hand sanitizer availability: N/A Application personnel: children and staff Hand sanitizer name and manufacturer: N/A Hand sanitizer composition (active ingredient): N/A Cost: not specified
Outcomes	Compliance with the hand hygiene program Outcome type: narrative Reporting: reported narratively Unit of measure: adherence to program Direction: greater compliance is favorable
Identification	Sponsorship source: unclear Country: Finland Setting: child day care centres, Oulu, Finland Comments: none Lead author's name: Matti Uhari Institution: Department of Pediatrics, University of Oulu Email: matti.uhari@oulu.fi Address: Matti Uhari MD, Department of Pediatrics, University of Oulu, FIN‐90220 Oulu, Finland
Notes	Comments: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Twenty CDCCs were randomly selected from the 53 municipal CDCCs in Oulu and paired on the basis of their size and the numbers and ages of the children attending them. One of the centers in each pair was then allocated for intervention at random according to random number tables." Judgement comment: low risk of bias as random number table was used for sequence generation.
Allocation concealment (selection bias)	Low risk	Quote: "Twenty CDCCs were randomly selected from the 53 municipal CDCCs in Oulu and paired on the basis of their size and the numbers and ages of the children attending them" Judgement comment: as eligibility criteria was confirmed and then randomized in pairs, allocation concealment would have occurred, however it was never stated when allocation between known to the investigators.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention, parents, staff and study nurses were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention, parents, staff and study nurses were not blinded.
Blinding of outcome assessment (detection bias) Compliance	High risk	Judgement comment: due to the nature of the intervention, parents, staff and study nurses were not blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "The parents of 48 children (6%) in the intervention CDCCs and 51 children (7%) in the control CDCCs refused to participate. In the control CDCCs 5.5% of the diaries were missing, and 5.6% were missing in the intervention CDCCs. The months with missing diaries were excluded from the person years at risk time" Judgement comment: the loss of data are similar across groups; therefore, we judged the potential for risk of bias to be low.
Selective reporting (reporting bias)	Unclear risk	Judgement comment: no protocol was mentioned in paper, and we did not find one during the search.
Other bias	High risk	Judgement comment: no ICC calculated and presentation of data does not facilitate the inclusion of this study data in formal meta‐analysis. Attempts were made to contact authors however they have failed to respond.

Vessey 2007.

Methods	Study design: cluster‐randomized controlled trial Study grouping: cross‐over Method to assess absenteeism data: school secretaries collected absentee information and specifically asked whether the absence was due to acute, communicable illnesses for students in study classrooms. When additional information was needed, the school nurse or teacher (or both) validated the reason for a student's absence. Method to classify a gastrointestinal event: acute, communicable illnesses; not defined Method to classify a respiratory illness: acute, communicable illnesses; not defined
Participants	Baseline characteristics Hand sanitizer Female (%): not specified Male (%): not specified Age distribution: not specified Participants: not specified Soap and water Female (%): not specified Male (%): not specified Age distribution: not specified Participants: not specified Overall Female (%): not specified Male (%): not specified Age distribution: not specified Participants: 360 Included criteria: grade 2 or 3 students in Butte, Montana school district Excluded criteria: kindergarten and 1st grade students, soap or sanitizer allergy Pretreatment: information not specified Time of the year conducted/season: January‐April (year not specified, assume 2007 or earlier) Country: USA Ethnicity: not specified Type of schooling: elementary schools in Montana school district (no further information provided) Class sizes: 15 to 27 students Gender distribution: not specified Age distribution: classes of years 2‐3 (ages not specified) Language spoken: not specified
Interventions	Intervention characteristics Hand sanitizer Education (who delivered the education and the format): a school nurse with content expertise but no affiliation with the school district data collectors taught the students in each designated class correct handwashing/sanitizing procedures using a standardized curriculum, including the video 'Wash those Hands' Concurrent activities: teachers, nurses, and other school personnel reminded all students to clean their hands as they normally would. A strict reminder protocol was not used; rather the intent was for teachers to give the reminders they normally would throughout the school day. Hand hygiene with soap and water instruction: instruction based on education session described above. Regular reminders given, such as before going to lunch and after using the bathroom, and episodic reminders, such as after activities that resulted in soiled hands Rinse‐free hand washing instruction (particularly regarding frequency of application): instruction based on education session described above. Regular reminders given, such as before going to lunch and after using the bathroom, and episodic reminders, such as after activities that resulted in soiled hands Hand sanitizer availability: available in their classrooms and restrooms Application personnel: students Hand sanitizer name and manufacturer: not specified Hand sanitizer composition (active ingredient): not specified Cost: not specified Soap and water Education (who delivered the education and the format): a school nurse with content expertise but no affiliation with the school district data collectors taught the students in each designated class correct handwashing/sanitizing procedures using a standardized curriculum, including the video 'Wash those Hands'. Concurrent activities: teachers, nurses, and other school personnel reminded all students to clean their hands as they normally would. A strict reminder protocol was not used; rather the intent was for teachers to give the reminders they normally would throughout the school day. Hand hygiene with soap and water instruction: instruction based on education session described above. Regular reminders given, such as before going to lunch and after using the bathroom, and episodic reminders, such as after activities that resulted in soiled hands Rinse‐free hand washing instruction (particularly regarding frequency of application): instruction based on education session described above. Regular reminders given, such as before going to lunch and after using the bathroom, and episodic reminders, such as after activities that resulted in soiled hands Hand sanitizer availability: available in their classrooms and restrooms Application personnel: students Hand sanitizer name and manufacturer: not specified Hand sanitizer composition (active ingredient): not specified Cost: not specified
Outcomes	Absenteeism due to any illness (outcome data were collected after direct contact with the authors, Vessey 2007) Outcome type: dichotomous outcome Reporting: days absent against child‐days possible; transformed to IRR by review authors Unit of measure: days Direction: lower is better Adverse skin reactions Outcome type: dichotomous outcome Reporting: children removed from study due to development of adverse skin reaction Unit of measure: events Direction: lower is better Perception of the hand hygiene strategy Outcome type: narrative Reporting: semi‐structured interviews provided to teachers to observe their perception of student RFHW usage Unit of measure: answers to surveys and structured interviews Direction: favorable perception is better
Identification	Sponsorship source: GOJO Industries Country: USA Setting: Elementary schools, Butte, Montana school district Comments: none Lead author's name: Judith A Vessey Institution: William F Connell School of Nursing, Chestnut Hill, MA Email: not specified Address: Connell School of Nursing, Chestnut hill, MA, USA
Notes	Comments Outcomes: badly written cross‐over study. All students were in both groups. Total days absent was 18 per intervention, out of a total of 360 students (review author Craig Lockwood on 13 February 2018 at 13:44). Outcomes: Absenteeism data had been collected after direct contact with the authors following email correspondence.(Silver 2018 [pers comm])
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Judgement comment: the study authors state that allocation was random but no further explanation is provided.
Allocation concealment (selection bias)	Unclear risk	Judgement comment: not clear how this process was completed and so we can not make a judgement on the risk of bias due to knowledge of allocation
Blinding of participants and personnel (performance bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention, school staff and researchers were not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention, school staff and researchers were not blinded. As school staff validated reasons for student absence there is a high risk of detection bias.
Blinding of outcome assessment (detection bias) Perception or satisfaction	High risk	Judgement comment: due to the nature of the intervention, school staff and researchers were not blinded. As school staff validated reasons for student absence there is a high risk of detection bias.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Judgement comment: due to the nature of the intervention, school staff and researchers were not blinded. As school staff validated reasons for student absence there is a high risk of detection bias.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Quote: "Of the 3 students who withdrew, 2 did so because the soap was too irritating and 1 because both soap and hand sanitizer were too irritating." Judgement comment: it is unclear which group those that withdrew were from
Incomplete outcome data (attrition bias) Absenteeism	Unclear risk	Quote: "Of the 3 students who withdrew, 2 did so because the soap was too irritating and 1 because both soap and hand sanitizer were too irritating." Judgement comment: it is unclear which group those that withdrew were from
Selective reporting (reporting bias)	Low risk	Judgement comment: the outcome reporting was limited to one primary measure ‐ absenteeism rates; therefore, unlikely that reporting was selective. This was the only outcome of interest to the authors.
Other bias	High risk	Judgement comment: the analysis did not include a control group; therefore, between‐group effects will have influenced the results due to an insufficient washout period. The review team calculated incidence rate ratios without adjusting for ICC of the individual study.

White 2001.

Methods	Study design: cluster‐randomized controlled trial Study grouping: parallel group Method to assess absenteeism data: teachers were responsible for recording attendance each day during the study. Parents provided detailed information on the nature of a student’s absence to the school office during the study. If the absence was for illness, a description of the symptoms was obtained. Absences were counted as either gastrointestinal, respiratory‐related, or "other"’(quote) non‐transmissible illness and non‐illness‐elated symptoms. Method to classify a gastrointestinal event: vomiting; abdominal pain; diarrhea ‐ details provided by parent Method to classify a respiratory illness: cough; sneezing; sinus trouble; bronchitis; fever alone; pink eye; headache; mononucleosis; and acute exacerbation of asthma ‐ details provided by parent
Participants	Baseline characteristics Rinse‐free hand washing program Female (%): not specified Male (%): not specified Age distribution: 5‐12 years Participants: 388 Control Female (%): not specified Male (%): not specified Age distribution: 5‐12 years Participants: 381 Overall Female (%): not specified Male (%): not specified Age distribution: 5‐12 years Participants: 769 Included criteria: parental consent Excluded criteria: children with known allergies to any of the ingredients in the SAB sanitizer were excluded from the study. Pretreatment: male/female ratios and age distributions of the study groups did not differ significantly. Time of the year conducted/season: March to April 1999 Country: USA Ethnicicty: not specified Type of schooling: elementary Class sizes: 20‐30 students Age distribution: 5‐12 years Gender distribution: not specified Language spoken: not specified
Interventions	Intervention characteristics Rinse‐free hand washing program Education (who delivered the education and the format): 2 weeks prior to study initiation, all students attended a 22‐minute assembly on proper handwashing technique, the importance of washing hands with soap and water to prevent the spread of illnesses, and the relationship of germs to illness. Students were taught new coughing and sneezing behaviors. During the assembly, students viewed a 4‐minute educational videotape (who delivered this is unclear). Concurrent activities: supplemented with normal (current pattern of utilization), at‐will hand washing with non medicated (non antibacterial) soap and water Hand hygiene with soap and water instruction: students were also instructed to wash hands at‐will with non medicated soap and water using proper hand washing technique when hands were soiled, after restroom use, and whenever necessary and possible throughout the day. At‐will hand washing was not supervised; however, the custodial staff at all school sites received a mandate to maintain adequate soap and paper towel supplies throughout the study period. Rinse‐free hand washing instruction (particularly regarding frequency of application): 6 times per day, in a classroom setting. The times determined for sanitizer use were (a) immediately upon entering the classroom, (b) before and after eating (recess and lunch), and (c) before leaving class at the end of the school day. Additional use was suggested after any child sneezed or coughed in the classroom. Hand sanitizer availability: children received a 1 oz bottle of the appropriate formulation fitted with a pump‐spray top; designed for use in the classroom setting. Application personnel: children Hand sanitizer name and manufacturer: alcohol‐free, instant hand sanitizer (SAB formulation), Woodward Laboratories Inc (CA, USA) Hand sanitizer composition (active ingredient): benzalkonium chloride (active ingredient) (SAB formulation) Cost: not specified Control Education (who delivered the education and the format): 2 weeks prior to study initiation, all students attended a 22‐minute assembly on proper hand washing technique, the importance of washing hands with soap and water to prevent the spread of illnesses, and the relationship of germs to illness. Students were taught new coughing and sneezing behaviors. During the assembly, students viewed a 4‐minute educational video tape (who delivered this is unclear). Concurrent Activities: supplemented with normal (current pattern of utilization), at‐will hand washing with non medicated (non antibacterial) soap and water Hand hygiene with soap and water instruction: students were also instructed to wash hands at‐will with non‐medicated soap and water using proper hand washing technique when hands were soiled, after restroom use, and whenever necessary and possible throughout the day. At‐will hand washing was not supervised; however, the custodial staff at all school sites received a mandate to maintain adequate soap and paper towel supplies throughout the study period. Rinse‐free hand washing instruction (particularly regarding frequency of application): 6 times per day, in a classroom setting. The times determined for sanitizer use were (a) immediately upon entering the classroom, (b) before and after eating (recess and lunch), and (c) before leaving class at the end of the school day. Additional use was suggested after any child sneezed or coughed in the classroom. Hand sanitizer availability: children received a 1 oz bottle of the appropriate formulation fitted with a pump‐spray top; designed for use in the classroom setting. Application personnel: children Hand sanitizer name and manufacturer: placebo; Woodward Laboratories Inc (CA, USA) Hand sanitizer composition (active ingredient): nonionic and amphoteric surfactants with allantoin, but without benzalkonium chloride or preservative compounds Cost: not specified
Outcomes	Absenteeism due to any illness Outcome type: dichotomous outcome Reporting: absence episodes over child‐days possible; transformed to IRR by review authors Unit of measure: episodes Direction: lower is better Adverse skin reactions Outcome type: narrative Reporting: children removed from study due to development of adverse skin reaction Unit of measure: events Direction: lower is better Absenteeism due to respiratory illness Outcome type: dichotomous outcome Reporting: absence episodes due to respiratory illness over child‐days possible; transformed to IRR by review authors Unit of measure: episodes Direction: lower is better Absenteeism due to gastrointestinal illness Outcome type: dichotomous outcome Reporting: absence episodes due to gastrointestinal illness over child‐days possible; transformed to IRR by review authors Unit of measure: episodes Direction: lower is better Compliance with the hand hygiene program Outcome type: narrative Reporting: reported narratively Unit of measure: adherence to program Direction: greater compliance is favorable
Identification	Sponsorship source: Orange County School Nurses Organization Health Promotion Grant Country: USA Setting: 1 private and 2 public elementary schools in California Comments: none Lead author's name: Catherine G White Institution: Los Alamitos Unified School District Email: not specified Address: Los Alamitos Unified School District, Los Alamitos, CA, USA
Notes	Comments Outcomes: 7 students were removed from the study due to skin rash issues. It is unclear if they were included in the analysis or not, or which group they belonged to (review author Craig Lockwood on 13 February 2018 at 14:23).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Children were randomly grouped by classroom". Judgement comment: authors state that children were randomized to their cluster, but insufficient information provided as to how this was achieved.
Allocation concealment (selection bias)	Unclear risk	Judgement comment: insufficient details were provided to enable a judgement to be made regarding allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Judgement comment: to distinguish contents, both the active and placebo formulations were distributed in four color‐coded groups of 1 oz spritz bottles. The contents and distribution patterns were known only to the researchers and were indecipherable by the school staff or students.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Judgement comment: due to the nature of the intervention, teachers and parents were not blinded and provided all absenteeism and compliance data to researchers.
Blinding of outcome assessment (detection bias) Compliance	High risk	Judgement comment: due to the nature of the intervention, teachers and parents were not blinded and provided all absenteeism and compliance data to researchers.
Blinding of outcome assessment (detection bias) Absenteeism	High risk	Judgement comment: due to the nature of the intervention, teachers and parents were not blinded and provided all absenteeism and compliance data to researchers.
Incomplete outcome data (attrition bias) All outcomes	High risk	Judgement comment: the data from the compliant classrooms demonstrating minimum adequate product use (at least 3 uses per day) were retained for analysis. Product usage was monitored by collecting and weighing individual bottles at the beginning, midpoint, and at end of the test period. Of the 72 initial classes involved in the study (1626 student participants), 32 classes (16 active and16 control; 769 student participants) were retained for analysis. The remainder of the classes were dropped from the data analysis because of noncompliance with minimum adequate product use standards.
Incomplete outcome data (attrition bias) Absenteeism	High risk	Judgement comment: the data from the compliant classrooms demonstrating minimum adequate product use (at least 3 uses per day) were retained for analysis. Product usage was monitored by collecting and weighing individual bottles at the beginning, midpoint, and at the end of the test period. Of the 72 initial classes involved in the study (1626 student participants), 32 classes (16 active and16 control; 769 student participants) were retained for analysis. The remainder of the classes were dropped from the data analysis because of noncompliance with minimum adequate product use standards.
Selective reporting (reporting bias)	Low risk	Judgment comment: trial protocol was not found, however outcomes specified in the methods have been reported in full in the results.
Other bias	High risk	Judgement comment: clear imbalance in baseline characteristics between groups. As we calculated incidence rate ratios without adjusting for ICC, this also represents a risk of bias.

ABH: alcohol based handrubs
 ADD: acute diarrheal disease
 AE(s): adverse event (adverse events)
 AGE: acute gastroenteritis
 ARI: acute respiratory illness
 AV: average
 CDC: Centers for Disease Control and Prevention
 CDCCs: child day‐care centres
 CG: control group
 DCC: day care centre
 GI: gastrointestinal
 HH: hand hygiene
 HSG: hand sanitizer group
 ICC: intra‐cluster correlation coefficient
 ILI: influenza‐like illness
 IRR: Incident rate ratio
 IT: Information technology
 MIDAS: Models of Infectious Disease Agent Study
 N/A: not applicable
 NIH: National Institutes of Health
 OR: odds ratio
 RFHW: rinse‐free hand wash
 RI: respiratory infection
 RT‐PCR: real time PCR
 SAB: surfactant, allantoin, benzalkonium chloride
 SD: standard deviation
 SEK: Swedish Krona
 SWG: soap and water group
 UNICEF: United Nations International Children's Emergency Fund
 URI: upper respiratory infection

Characteristics of excluded studies [ordered by study ID]

Study	Reason for exclusion
Alexander 2013	Ineligible intervention
Alzaher 2018	Ineligible intervention
Appiah‐Brempong 2020	Ineligible intervention
Arbianingsih 2018	Ineligible intervention
Arikan 2018	Ineligible intervention
Au 2010	Ineligible intervention
Bartlett 1988	Ineligible intervention
Black 1981	Ineligible intervention
Bonnesen 2015	Ineligible intervention
Bowen 2007	Ineligible intervention
Bulled 2017	Ineligible intervention
Butz 1990	Ineligible patient population
Carabin 1999	Ineligible intervention
Caruso 2014	Ineligible intervention
Chard 2018	Ineligible intervention
Chard 2019	Ineligible intervention
ChiCTR1900023346	Ineligible intervention
Denbæk 2018	Ineligible intervention
Dingman 2020	Ineligible intervention
Erismann 2017	Ineligible intervention
Jess 2019	Ineligible intervention
Kotch 2007	Ineligible intervention
Kusbaryanto 2017	Ineligible intervention
Ladegaard 1999	Ineligible intervention
Lange 2019	Ineligible intervention
Lee 2015	Ineligible intervention
Lim 2019	Ineligible intervention
Liu 2019	Ineligible intervention
Luby 2005	Ineligible intervention
Mangklakeeree 2013	Ineligible intervention
Mangklakeree 2014	Ineligible intervention
Master 1997	Ineligible intervention
Mbakaya 2019	Ineligible intervention
Mendes 2020	Ineligible intervention
Mohamed 2018	Ineligible intervention
Mohamed 2019	Ineligible intervention
Mohd 2020	Ineligible intervention
Nandrup Bus 2009	Ineligible intervention
Nandrup Bus 2011	Ineligible study design
Nicholson 2014	Ineligible intervention
Nnoaham 2006	Ineligible intervention
Or 2019	Ineligible intervention
Or 2020	Ineligible intervention
Panknin 2007	Ineligible intervention
Pete 1987	Ineligible study design
Planet Water Foundation	Ineligible intervention
Ramseier 2007	Ineligible intervention
Randle 2013	Ineligible intervention
Roberts 2000	Ineligible intervention
Rosen 2006	Ineligible intervention
Saboori 2013	Ineligible intervention
Soto 1994	Ineligible intervention
Talaat 2011	Ineligible intervention
Trinies 2014	Ineligible intervention
Wichaidit 2016	Ineligible intervention
Zhou 2015	Ineligible intervention
Zomer 2015	Ineligible patient population
Öncu 2019	Ineligible intervention

Differences between protocol and review

1. Title

   1. In response to external feedback, we removed 'aged' from 'school‐aged children' in the title and throughout the review, to acknowledge the fact that not all school‐aged children attend school, and that studies assessed the impact of rinse‐free hand wash on children who attended school.

2. Author team

   1. Timothy Hugh Barker and Helen McAneney joined the author team.

3. Objectives

   1. Changed some of the wording for our first objective from what was previously published in the protocol (Munn 2017), to highlight we are interested in absenteeism for any reason or due to illness.

4. Electronic searches

   1. We searched Epistemonikos in place of DARE (Database of Abstracts of Reviews of Effects), which ceased to be updated in 2015.

   2. We attempted to update the search in DoPHER in 2020, but the database was unresponsive.

   3. We did not search 3ie as planned as it was overlooked by the review team after communication issues with the information scientist. This was identified at a later date but it was felt that it was unnecessary to search this resource at the time of the top‐up searching.

5. Measures of treatment effect > Dichotomous data

   1. For adverse events, we used relative risks as opposed to odds ratios, to assist in interpreting the results.

   2. For our analyses, we needed to convert data and we did not specify how we would do this in our protocol (Munn 2017).

   3. When reviewing the included studies, it was clear that our planned approach to assess absenteeism with relative risks was not appropriate, so we ended up using incidence rate ratio as the preferred effect measure.

6. Unit of analysis issues

   1. Where studies did not take clustering into consideration, we did not analyze clusters as if the randomization process was performed on the individuals rather than the clusters (Higgins 2011b). We requested the individual participant data to calculate an estimate of the intra‐cluster correlation coefficient (ICC), however, we did not obtain estimates of the clustering effect from external sources and therefore were unable to use these to reanalyze the data to obtain the approximately correct analyses. As such, we either used the incidence rate ratio (IRR) provided by the study, or calculated our own based on the data provided in the report.

7. Summary of findings

   1. In line with current guidance, we now refer to the 'certainty' of the evidence, instead of 'quality' of the evidence as specified in our protocol (Munn 2017).

Contributions of authors

All authors contributed to the development of this review.

ZM drafted the protocol and incorporated feedback from other group members. ZM participated in all stages of the review, including contributing to the development of the GRADE 'Summary of findings' tables.
 CT assisted with searching for literature and writing the protocol and review, including methodological guidance.
 CL conceptualized the idea and focus of the review, and assisted with drafting the protocol and review. CL participated in study selection, screening, extraction and revisions of the main text at review stage.
 CS contributed to the draft of the protocol and provided feedback. CS participated in study selection, screening, extraction and revisions of the main text at review stage.
 HMcA provided input and feedback on the statistical approaches and contributed to the writing of the final version of the review.
 TB participated in the screening and selection from the updated searches and additional 'Risk of bias' assessments and data extraction at the review stage, drafted the results and performed the GRADE assessment.

ZM is the guarantor for the review.

Sources of support

Internal sources

• Joanna Briggs Institute, Australia.

  Employer of ZM, CL, CS, TB

• Queen's University Belfast, UK.

  Employer of HM

• Macquarie University, Australia.

  Employer of CT

External sources

• No sources of support supplied

Declarations of interest

ZM — none known.
 CT — received royalties from WK Lippincott Williams and Wilkins for two books 'Statistics for Systematic Review Authors' and 'Synthesizing Economic Evidence'. CT declares that the contents of these books are not related to the review and that there is no information in either book about the interventions investigated in this review.
 CL — none known.
 CS — none known.
 HA — is a Statistical Editor with Cochrane Developmental, Psychosocial and Learning Problems.
 TB — none known.

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