Community-level barriers and facilitators of indoor residual spraying for malaria control: a systematic review of qualitative evidence from sub-Saharan Africa

Abstract

Introduction

Indoor residual spraying is a key strategy in the control against malaria, which still remains a devastating public health challenge in Sub-Saharan Africa. It was recommended by the World Health Organization, yet its effectiveness is still being compromised by low community uptake. Unlike other malaria interventions, indoor residual spraying is intrusive and requires entry into private household spaces and substantial domestic preparation. Household refusal and locked structures still remain primary threats to the success of the campaign. Although qualitative studies have examined community perceptions of indoor residual spraying, their findings remain dispersed and have not been systematically synthesised.

Methods

A systematic review and qualitative evidence synthesis was conducted following the Enhancing Transparency in Reporting the Synthesis of Qualitative Research guidelines. Four electronic databases (PubMed, Scopus, Web of Science, and CINAHL) were searched for peer-reviewed qualitative studies published between 2010 and May 2024. Studies were selected using the Sample, Phenomenon of Interest, Design, Evaluation, and Research Type framework and appraised using the Critical Appraisal Skills Programme qualitative checklist. Thematic synthesis was undertaken through line-by-line coding and the development of descriptive themes.

Results

The systematic search yielded 321 records. Ten studies from seven Sub-Saharan African countries met the full inclusion criteria. Eight major analytical themes emerged: (1) operational and household burdens, particularly the labor required to prepare homes; (2) perceived efficacy and cognitive factors, including concerns about bedbugs and visible insect control; (3) socio-political dynamics and trust in authorities; (4) programmatic communication and sprayer conduct; (5) gender dynamics in household decision-making; (6) structural and seasonal incompatibility; (7) implementation strategy and spatial equity; and (8) endorsement systems and local health infrastructure.

Conclusion

Community engagement with indoor residual spraying is shaped by complex social, gendered, and political factors involving labor, gender, and privacy rights. Coverage requires a shift toward human-centered implementation approaches that reduce household labor burdens, address concerns about nuisance insects, ensure respectful sprayer conduct, and strengthen community trust. Integrating these considerations into indoor residual spraying programs is essential for sustaining effective malaria control in Sub-Saharan Africa.

PROSPERO Registration number: CRD420251248457.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-026-05937-6.

Introduction

Malaria remains a devastating public health challenge in Sub-Saharan Africa, which accounted for approximately 95% of global malaria cases and 96% of global malaria-specific deaths in 2022 [1]. Despite the scale-up of core interventions, progress has stalled in many high-burden countries, driven by threats such as insecticide resistance, climate change, and gaps in health system coverage [2]. To regain momentum toward the targets of the Global Technical Strategy for Malaria 2016–2030, the World Health Organization emphasizes the need for maximal coverage of vector control interventions, primarily Long-Lasting Insecticidal Nets (LLINs) and Indoor Residual Spraying (IRS) [3].

IRS, the application of long-acting chemical insecticides to the interior walls of potential vector resting sites, is a highly effective method for rapidly reducing vector density and longevity [4, 5]. When implemented correctly with high coverage, typically exceeding 80% of eligible structures, IRS can interrupt local transmission [6]. However, the effectiveness of IRS is inextricably linked to community acceptance in a way that differs fundamentally from other interventions. Unlike LLINs, which are user-controlled, IRS is an intrusive, top-down intervention. It requires homeowners to allow strangers (spray operators) into their most private domestic spaces, remove all household belongings, and vacate the premises for several hours.

This “intrusion” creates a unique interface between the health system and the community, where trust, privacy, and convenience are tested during every spray round. Operational reports frequently cite “household refusal” and “locked structures” as primary threats to campaign success [7]. While quantitative Knowledge, Attitude, and Practice surveys have attempted to categorize these refusals, often citing reasons such as “smell” or “inconvenience” [8, 9], they fail to capture the nuanced social, political, and gendered dynamics that underpin a household’s decision to open their door. For example, why do “educated” individuals in Tanzania refuse spraying more often than the general population? [10], Why does the presence of bedbugs in Rwanda lead to the rejection of malaria control? [11].

Qualitative research offers the methodological depth to answer these questions. Over the past decade, isolated qualitative studies have explored these dynamics, yet their findings remain scattered. To date, there has been no comprehensive qualitative synthesis of community experiences with IRS in Sub-Saharan Africa. This systematic review aims to fill this gap by identifying, appraising, and synthesizing qualitative evidence on the barriers and facilitators to community engagement with IRS. By mapping these factors, we aim to provide actionable recommendations for National Malaria Control Programs to design more acceptable, community-centered IRS campaigns.

Methods

Protocol and registration

This systematic review was conducted in accordance with the Enhancing Transparency in Reporting the Synthesis of Qualitative Research (ENTREQ) guidelines [12]. The ENTREQ guidelines provide a 21-item framework to improve the reporting of qualitative evidence syntheses, covering areas including search strategy, study selection, appraisal, and synthesis thereby ensuring methodological transparency and reproducibility. The protocol was developed a priori and includes a defined search strategy, inclusion/exclusion criteria, and analysis plan. The PROSPERO (International Prospective Register of Systematic Reviews) under registration number is CRD420251248457.

Research questions

The overarching research question guiding this review is: What are the community-level barriers and facilitators to engagement with indoor residual spraying for malaria control in sub-Saharan Africa, as reported in qualitative studies? Specifically, we sought to identify: (1) what factors prevent households from accepting or cooperating with IRS campaigns; and (2) what programmatic, social, and contextual factors facilitate community acceptance and participation.

Search strategy

We conducted a comprehensive search of four electronic databases: PubMed, Scopus, Web of Science, and CINAHL. The search was conducted on February 1st, 2026 and limited to peer-reviewed articles published from inception to the January 2026. The search strategy combined terms for Intervention (“Indoor Residual Spraying”, “IRS”, “Vector Control”), Phenomenon of Interest (“Acceptability”, “Perception”, “Barrier”, “Facilitator”, “Community Engagement”, “Refusal”), Study Design (“Qualitative”, “Focus Group”, “Interview”, “Ethnography”), and Setting (“Sub-Saharan Africa”, “Africa”). Boolean operators (AND/OR) were used to refine the results. We also hand-searched the reference lists of included studies and relevant reviews to identify additional literature. Example PubMed search detailed in Table 1. Detailed search strategy from all databases can be found in additional file (see Additional file 1).

Table 1.

PubMed search strategy

((“indoor residual spray”[tiab] OR “indoor residual spraying”[tiab] OR IRS[tiab])
AND (malaria[tiab] OR “vector control”[tiab])
AND (community[tiab] OR household*[tiab] OR accept*[tiab] OR uptake[tiab]
OR refusal[tiab] OR perception*[tiab] OR attitude*[tiab] OR belief*[tiab])
AND (qualitative[tiab] OR “focus group”[tiab] OR interview*[tiab]
OR ethnograph*[tiab] OR “participant observation”[tiab])
AND (“Africa South of the Sahara”[M
esh] OR “Sub-Saharan Africa”[tiab]
OR Angola[tiab] OR Benin[tiab] OR Botswana[tiab] OR Burkina Faso[tiab]
OR Burundi[tiab] OR Cameroon[tiab] OR Chad[tiab] OR Congo[tiab] OR
“Democratic Republic of the Congo”[tiab] OR Ethiopia[tiab] OR Ghana[tiab]
OR Kenya[tiab] OR Malawi[tiab] OR Mozambique[tiab] OR Nigeria[tiab]
OR Rwanda[tiab] OR Senegal[tiab] OR Tanzania[tiab] OR Uganda[tiab]
OR Zambia[tiab] OR Zimbabwe[tiab]))

Study selection

Duplicate records were removed using Covidence systematic review software prior to screening. Two independent reviewers (IP and PMO) screened all titles and abstracts against the SPIDER inclusion criteria. Full-text articles were then retrieved for all records passing title/abstract screening. Full-text screening was conducted independently by IP and PMO, with a third reviewer (LA) available to adjudicate disagreements. Discrepancies at each stage were resolved through structured discussion until consensus was reached. Reference lists of all included studies and relevant systematic reviews were searched to identify additional eligible studies not captured by the electronic database search.

Inclusion and exclusion criteria

Studies were selected based on the SPIDER framework (Sample, Phenomenon of Interest, Design, Evaluation, Research Type) [13].

• Sample: Community members, local leaders, and spray operators in Sub-Saharan Africa.

• Phenomenon of interest: Barriers and facilitators to acceptance, uptake, refusal, and adherence to IRS.

• Design: Primary qualitative studies (such as Focus Group Discussions [FGDs], Key Informant Interviews [KIIs], Ethnography) or mixed-methods studies where qualitative data were distinct and extractable.

• Evaluation: Perspectives on community engagement and acceptance.

• Research type: Peer-reviewed original research articles published in English.

Studies were excluded if they were purely quantitative (such as randomized controlled trials reporting only bio-efficacy or coverage statistics), policy analyses without primary data, or focused on vectors other than malaria (such as visceral leishmaniasis).

Data extraction

A structured data extraction form was developed a priori and piloted on two studies before full implementation. The following data were extracted from each included study: (1) study citation (author, year, country); (2) study aim and design; (3) participant characteristics; (4) IRS intervention details; (5) data collection methods (FGDs, KIIs, IDIs, ethnography); (6) key barriers to IRS acceptance; (7) key facilitators of IRS acceptance; and (8) author-reported conclusions. Data extraction was performed independently by two reviewers (IP and PMO) using Microsoft Excel. A third reviewer (LA) cross-checked all extracted data for completeness and accuracy. Discrepancies were resolved through discussion. No additional data extraction software was used beyond ATLAS.ti v23, which was used for qualitative coding and thematic synthesis.

Quality appraisal

Two reviewers (IP and PMO) independently assessed the methodological rigor of the included studies using the CASP (Critical Appraisal Skills Programme) Qualitative Checklist [14]. This 10-item tool assesses study validity, including the appropriateness of the research design, recruitment strategy, data collection, and reflexivity. All included studies were deemed of moderate to high quality, with clear statements of findings and valuable contributions to the research question. Details are in additional file (see Additional file 2).

Data analysis and synthesis

We employed thematic synthesis following the three-stage approach described by Thomas and Harden [15]. All analysis was done in ATLAS.ti v23. The three-stage synthesis process explicitly addressed our research question at each stage: Stage 1 (line-by-line coding of “Results” and “Discussion” sections of all included papers) generated initial descriptive codes representing community-reported experiences; Stage 2 (development of descriptive themes) grouped related codes into coherent descriptive categories (e.g., ‘fear of theft’ and ‘fear of strangers’ combined into ‘Trust in Sprayers’); and Stage 3 (development of analytical themes) synthesized descriptive themes into higher-order explanatory constructs that directly mapped onto the barriers and facilitators identified in our research question, going beyond the findings of individual studies to generate new interpretive insight.

Results

Study selection and characteristics

The systematic search yielded 321 records. After deduplication and screening in Covidence, 10 studies met the full inclusion criteria (Fig. 1). These studies were conducted in Mozambique (n = 3), Uganda (n = 2), Tanzania (n = 1), Zambia (n = 1), Rwanda (n = 1), Ghana (n = 1), and Namibia (n = 1). The studies employed diverse qualitative and mixed-methods approaches, involving approximately 115 focus group discussions and over 250 in-depth interviews. Details are included in Table 2.

Fig. 1.

PRISMA flow diagram showing the screening process of the included studies

Table 2.

Summary of characteristics of included studies

Author	Study location	Study aim	Methodology	Participants	Intervention	Key facilitators for engagement	Key barriers to engagement
Montgomery et al. [16]	Manhiça District, Mozambique	To understand IRS acceptability in the context of policy, politics, and historical processes	Qualitative: anthropological research (FGDs, IDIs, observations)	Household heads, community leaders, and sprayers	Indoor residual spraying (IRS)	Group-based citizenship; sense of social duty and obedience to health authorities	Political fragmentation; refusal of IRS used as a proxy for political dissatisfaction
Munguambe et al. [17]	Manhiça District, Mozambique	To explore factors associated with community adherence and acceptability of IRS	Qualitative: IDIs, participant observation, and FGDs	Householders, community leaders, health providers, and sprayers	Indoor residual spraying (IRS)	Perceived collateral benefits (killing non-target pests like cockroaches/flies)	Heavy domestic labor required to move furniture before spraying; gendered burden on women
Kaufman et al. [10]	Mainland Tanzania and Zanzibar	To identify attitudes and misconceptions related to the acceptance or refusal of IRS	Qualitative: semi-structured IDIs and FGDs	Acceptors, refusers, farmers, fishermen, and community leaders	Indoor residual spraying (IRS)	Belief that IRS protects children and reduces overall malaria suffering	Misconceptions about toxicity; physical effort of “packing” rooms; male absence during visits
Ingabire et al. [11]	Ruhuha, South Eastern Rwanda	To explore factors hindering the use of malaria preventive measures like LLINs and IRS	Qualitative: 9 FGDs	Community members and local leaders	IRS and long-lasting insecticidal nets (LLINs)	General desire for malaria elimination and high perceived risk of the disease	The “bedbug paradox” (belief that IRS makes bedbugs more active or resistant)
Wanzira et al. [19]	Katakwi District, Uganda	To identify facilitators and barriers for both MDA and IRS implementation	Qualitative: KIIs and FGDs	District personnel, medical staff, and community members	IRS and mass drug administration (MDA)	Use of local languages; radio-based social mobilization; engagement of local leaders	Toxicological fears (odors); seasonal issues (rain making drying/moving items difficult)
Magaço et al. [21]	Mozambique (Multiple Provinces)	To evaluate community factors related to IRS acceptability following high refusal rates	Qualitative: IDIs, FGDs, field observations	Acceptors, refusers, leaders, and district health representatives	Indoor residual spraying (IRS)	Alignment with official health recommendations and government initiatives	Mistrust of sprayers; political associations (sprayers linked to specific political parties)
Suuron et al. [18]	Upper West Region, Ghana	To explore barriers and facilitators to IRS uptake using the health belief model	Qualitative: FGDs and semi-structured interviews	Community members, spray operators, and program officials	Indoor residual spraying (IRS)	Clear programmatic communication; understanding of IRS as a preventive tool	Religious/cultural beliefs (shrines in homes); unprofessional sprayer conduct (theft)
Roberts et al. [23]	Zambezi Region, Namibia	To assess community acceptability of reactive focal MDA and reactive focal vector control	Mixed-methods: 17 KIIs and 49 FGDs	Community members, leaders, NGOs, and government staff	Reactive focal vector control (RAVC) using IRS	Strong social cohesion; endorsement by traditional village authorities	Unannounced arrival of sprayers; lack of information on “reactive” vs. “mass” spraying
Tembo [22]	Chipushi Area, Mpika, Zambia	To analyze factors contributing to non-acceptance of IRS in a rural setting	Mixed-methods: Questionnaires and semi-structured interviews	97 community respondents	Indoor residual spraying (IRS)	Targeted health education and increased community awareness	“Shame of housing” (exposing poverty inside); belief that spray increases bedbugs
Ocan et al. [20]	Multiple Districts, Uganda	To explore perceptions on the effectiveness and safety of IRS for malaria control	Qualitative: 16 FGDs and 23 KIIs	Household heads, health workers, and village health teams	Indoor residual spraying (IRS)	Evidence of fewer mosquitoes/bugs; trust in village health teams	Skin irritation; allergic reactions; perception that IRS chemical is “fake” if bugs return

IRS indoor residual spraying, LLINs long-lasting insecticidal nets, MDA mass drug administration, rfMDA reactive focal mass drug administration, RAVC reactive focal vector control, FGDs focus group discussions, IDIs in-depth interviews, KIIs key informant interviews

Thematic synthesis

The analysis generated eight major analytical themes: (1) Operational and Household Burdens [10, 16–20]; (2) Perceived Efficacy and Cognitive Factors [11, 17, 18, 20–22]; (3) Socio-Political Dynamics and Trust [16, 17, 21]; (4) Programmatic Communication and Conduct [18, 19, 21, 23]; (5) Gender Dynamics and Household Decision-Making [10, 17]; (6) Structural and Seasonal Incompatibility [10, 19, 22]; (7) Implementation Strategy and Spatial Equity [23]; and (8) Endorsement Systems and Local Health Infrastructure [16, 19, 20, 23].

Theme 1: Operational and household burdens

IRS requires a significant physical disruption of the domestic space. This theme captures the logistical costs households must pay to participate.

• The labor of “packing”: A universal barrier was the intense physical labor required to remove all household goods, food, and heavy furniture before spraying. This was particularly prohibitive for the elderly or female-headed households. Kaufman et al. [10] noted:

To be honest, the exercise is difficult... You have to take out everything, the bedding, the pots, the food, everything. And then you have to wait outside for hours. It is too much work for us, especially when you are old and have no one to help you. (Female Community Member, Tanzania)

• Intrusion into private and spiritual spaces: The entry of strangers into bedrooms triggered anxiety regarding privacy. In Ghana, this clashed with spiritual beliefs regarding shrines kept in sleeping quarters. Suuron et al. [18] reported:

We have our smaller gods in the rooms and it is not allowed for just anyone to enter there. The sprayers are strangers, and if they enter, they might see things they are not supposed to see. (Community Elder, Ghana)

• Toxicological fears and physical reactions: The physical side effects of the insecticide were a major deterrent. Ocan et al. [20] highlighted that acute physical responses post-spraying directly drove household refusals:

After they sprayed, my skin started itching so much, and my children got rashes. The medicine is too strong for our bodies. If the medicine is killing insects, what is it doing to our lungs? (Key Informant, Uganda)

Theme 2: Perceived efficacy and cognitive factors

Community acceptance was often decoupled from a biomedical understanding of malaria. Instead, residents weighed the “visible” impact of the spray against its “invisible” malaria benefits.

• The “bedbug paradox”: A pervasive barrier was the belief that IRS chemicals failed to kill bedbugs or actively agitated them, making the infestation worse. Ingabire et al. [11] reported:

Since they sprayed, the bedbugs have increased. It is like the medicine gives them power... Better mosquitoes than these bedbugs. (FGD Participant, Rwanda)

• The “fake chemical” perception: Acceptance was highly contingent on observable lethality. If mosquitoes returned shortly after spraying, residents concluded the chemical was diluted. Ocan et al. [20] noted:

They spray today, and tomorrow you see mosquitoes flying around just the same. This makes people think the government is just mixing water or the medicine has expired. (FGD Participant, Uganda)

• Collateral benefits: Conversely, when the spray killed visible nuisance insects, this acted as a powerful facilitator. Munguambe et al. [17] found:

What we really like about the spray is that it kills all the cockroaches, fleas, and flies. The house becomes very clean. Even if it doesn’t stop malaria, it gets rid of the pests. (Household Head, Mozambique)

Theme 3: Socio-political dynamics and trust

Participation was often driven by social duty or political alignment rather than health beliefs.

• “Group-based citizenship”: Acceptance was often seen as a form of “civic duty” and obedience to health authorities. Montgomery et al. [16] described:

This is government business. When the government says ‘spray’, we spray. Who am I to say no? If I say no, I am separating myself from the community. (Community Leader, Mozambique)

• Political distrust: In politically fragmented areas, IRS became a proxy for political dissatisfaction. Magaço et al. [21] noted:

Some people refuse because they think the sprayers are sent by the ruling party. They say, ‘We don’t belong to that party, so we don’t want their medicine in our houses.’ (Community Member, Mozambique)

Theme 4: Programmatic communication and conduct

The behavior of the spray teams was a critical determinant of trust.

• Sprayer conduct: Reports of theft or disrespect led to permanent refusal. Suuron et al. [18] highlighted:

Sometimes the spray operators do not behave well. They are rude to the women, or we hear stories that small items go missing when they are in the rooms alone. (FGD Participant, Ghana)

• The information gap: Refusals were linked to “top-down” approaches where sprayers arrived without prior engagement. Suuron et al. [18] also reported:

They just come with their machines and say ‘open the door’. They don’t explain what the medicine is... They treat us like we don’t know anything. (FGD Participant, Ghana)

Theme 5: Gender dynamics and household decision-making

This theme highlights the disconnect between those who bear the labor burden (women) and those who decide (men).

• Male absenteeism: A major barrier was the absence of the male head of household. Women often refused entry without their husband’s permission. Kaufman et al. [10] found:

I cannot just allow strangers into the house when my husband is away at the farm. If something is damaged or missing, he will blame me. It is better to wait until he is around. (Female FGD Participant, Tanzania)

• The female labor burden: While men made the decision to accept, the heavy labor of moving furniture fell disproportionately on women. Munguambe et al. [17] observed:

The men just say ‘yes’ to the sprayers, but they leave for work. It is us women who have to carry the heavy beds and pots outside, and then put them all back again. (Female FGD Participant, Mozambique)

Theme 6: Structural and seasonal incompatibility

• Shame of housing conditions: Poverty led to refusals due to the shame of exposing dilapidated interiors to strangers. Tembo [22] reported:

People are embarrassed. When the sprayers come, they see that you don’t have good furniture, or that your roof is leaking. It brings shame to the family to expose this poverty. (Community Member, Zambia)

• Seasonal misalignment: Spraying during the rainy season made moving goods outside impossible. Wanzira et al. [19] noted:

They bring the spray during the rainy season. How can we take our bedding and food outside when it is raining? It will all get ruined. (FGD Participant, Uganda)

Theme 7: Implementation strategy and spatial equity

This theme addresses community responses to the shifting nature of IRS deployment, particularly focal/reactive spraying.

• Confusion over focal/reactive targeting: When IRS transitions to a reactive strategy, it generates confusion compared to mass campaigns. Roberts et al. [23] observed:

Before, they used to announce on the radio and spray the whole village. Now, they just appear at one house quietly. People don’t understand this new way. (Community Leader, Namibia)

• Perceived inequity and exclusion: Targeted spraying often led to suspicion and feelings of neglect. Roberts et al. [23] noted:

They spray my neighbour’s house but leave mine. Mosquitoes do not respect fences. Why protect one person and leave the other to suffer? (FGD Participant, Namibia)

Theme 8: Endorsement systems and local health infrastructure

The acceptance of IRS is heavily mediated by who delivers the message.

• The mediating role of Village Health Teams (VHTs): External spray teams are viewed with suspicion, but local health workers act as critical bridges. Ocan et al. [20] emphasized:

We trust the VHTs because they live with us. When they come with the sprayers and tell us the chemical is safe, we agree. If it is just strangers from the district, people hide. (Household Head, Uganda)

• Traditional authority and social cohesion: In areas with strong traditional governance, program success hinges on leadership buy-in. Roberts et al. [23] demonstrated:

If the Induna (headman) has agreed to the spraying, everyone must follow. He has consulted with the health teams, so we know it is for the good of the village. (Community Member, Namibia)

Discussion

This qualitative evidence synthesis identifies eight interacting determinants of community IRS acceptance in Sub-Saharan Africa. The primary barriers, ranked by frequency and cross-study consistency, are: (1) the disproportionate physical labor required to prepare households (‘packing’), especially for elderly and female-headed households; (2) toxicological fears and adverse physical reactions experienced after spraying; (3) political distrust, where IRS is perceived as a tool of political parties rather than public health; (4) unprofessional sprayer conduct including reports of theft, rudeness, and unannounced arrivals; (5) the ‘bedbug paradox,’ where IRS is perceived to worsen bedbug infestations; (6) seasonal misalignment between spray schedules and local livelihood activities; (7) gender inequity in the distribution of household preparation labor; and (8) confusion and perceived spatial inequity arising from targeted or focal spraying strategies.

Conversely, the primary facilitators are: (1) endorsement by Village Health Teams (VHTs) and traditional authorities who are trusted community bridges; (2) the observable collateral benefit of killing nuisance insects (cockroaches, flies); (3) a community sense of civic duty when IRS is framed as a collective responsibility; (4) effective advance sensitization in local languages; and (5) the demonstrated reduction in mosquito density providing tangible, proximal evidence of efficacy.

This qualitative evidence synthesis therefore reveals that community acceptance of IRS in Sub-Saharan Africa extends far beyond a simple binary of health literacy versus ignorance. Instead, household participation is a complex negotiation involving logistical burdens, perceived efficacy, socio-political trust, and spatial equity. By synthesizing evidence across diverse epidemiological contexts, this review highlights that the success of IRS depends as much on the social and operational dynamics of its delivery as it does on the entomological efficacy of the insecticide.

A dominant theme across the synthesized studies is the disconnect between the biomedical goals of malaria control programs and the lived realities of communities. While global health priorities emphasize IRS as a critical tool especially given the waning efficacy of the RTS’S vaccine and the growing threat of parasite resistance to artemisinin-based combination therapies [1] communities evaluate IRS through immediate, observable outcomes. The “bedbug paradox” and the “fake chemical” perception [20] directly threaten program sustainability. When residents observe that nuisance insects survive or proliferate post-spraying, trust in the intervention collapses. This qualitative finding conceptually aligns with the macro-level challenges of escalating vector resistance to pyrethroids and organophosphates [1]; what communities interpret as “diluted” or “fake” government chemicals may, in fact, be the early epidemiological indicators of insecticide resistance.

Two barriers from our synthesis deserve particular emphasis in the context of program design and cultural competence. First, the intrusion into spiritually significant private spaces documented specifically in Ghana [18], where shrines and sacred objects kept in sleeping quarters created a profound barrier to IRS represents a category of refusal that is categorically different from logistical inconvenience. No amount of community sensitization about malaria transmission biology can override deeply held spiritual convictions unless spray programs explicitly acknowledge and accommodate these beliefs. Practically, this requires that spray teams include, or consult with, community members who understand local sacred practices, and that programs develop flexible, negotiated entry protocols for households with spiritually protected spaces. Second, the documented physical reactions to IRS chemicals including skin rashes, irritation, and respiratory symptoms experienced by household members post-spraying [4, 19] represent both a genuine public health concern and a powerful driver of permanent refusal. These reactions, whether attributable to specific insecticide formulations or individual sensitivities, must be treated as legitimate adverse events within the IRS program framework, with clear reporting mechanisms and care pathways for affected community members.

Quantitative assessments often demonstrate high community knowledge regarding malaria transmission and general acceptance of vector control tools. For instance, Jumbam et al. [9] demonstrated robust baseline knowledge and acceptance of IRS and insecticide-treated nets in rural Zambia. However, our qualitative synthesis explains why this knowledge does not always translate into action. The overwhelming operational burden specifically the intense physical labor required to “pack” a house, coupled with toxicological fears and seasonal incompatibilities frequently overrides positive health beliefs. Furthermore, gender dynamics play a crucial role; while male heads of household typically consent to the intervention, the heavy labor of moving furniture and the stress of intruded domestic spaces fall disproportionately on women.

Traditional normative guidance has dictated that IRS must achieve 80–85% household coverage to confer community-level protection. However, recent retrospective causal inference analyses, such as those by Galick et al. [6] on Bioko Island, suggest that significant reductions in malaria incidence can be achieved at lower, more flexible coverage thresholds. This evolving understanding of dose–response in IRS coverage has profound implications for our qualitative findings. The rigid pursuit of > 80% coverage often drives the “top-down” programmatic conduct and unannounced sprayer arrivals that generate community resentment and fuel political distrust. If lower, targeted coverage can still provide community protection [6], programs can afford to transition from coercive mass campaigns to more deliberate, community-led deployment strategies.

However, transitioning to targeted or reactive focal vector control (RAVC) introduces new social challenges. Another study identified, focal spraying can breed suspicion of spatial inequity, where skipped households feel politically neglected or assume favoritism [23]. Thus, any shift away from blanket mass campaigns requires hyper-localized communication strategies mediated by trusted entities, such as Village Health Teams or traditional authorities, to explain the epidemiological rationale behind spatial targeting.

Implications for public health practice and policy

The findings of this synthesis necessitate a paradigm shift in how malaria vector control programs are designed, implemented, and evaluated in Sub-Saharan Africa. Public health authorities must move beyond defining IRS success solely through entomological indicators and geographical coverage metrics, and actively integrate socio-behavioral indicators of community trust and household burden. Practically, this requires decentering “top-down” campaign models in favor of community co-design. Programs must explicitly account for the gendered labor of IRS preparation such as providing logistical support for elderly or female-headed households to move heavy furniture and align spraying schedules with local seasonal realities rather than rigid external funding timelines. Furthermore, as malaria control strategies increasingly transition from blanket campaigns to targeted or reactive focal spraying, public health messaging must evolve to transparently explain the epidemiological rationale behind spatial selection to prevent feelings of inequity or political exclusion. Ultimately, embedding IRS campaigns within the trusted, permanent infrastructure of Village Health Teams (VHTs) and traditional leadership, rather than relying on external and transient spray operators, is critical for sustaining the community adherence required to achieve malaria elimination.

Actionable recommendations

Based on the synthesized evidence, we propose the following five actionable recommendations for National Malaria Control Programs in Sub-Saharan Africa:

Recommendation 1: Institutionalize advance notification and community pre-engagement. Programs must mandate structured, multi-channel pre-spray sensitization at least 2 weeks before campaign commencement, delivered via local radio, community meetings, and local language messaging. This directly addresses the information gap identified across multiple studies, where unannounced spray-team arrivals were a primary driver of refusal.

Recommendation 2: Provide logistical support for vulnerable households. Spray campaigns should incorporate a ‘household assistance protocol’ for elderly, disabled, or female-headed households who cannot independently manage the labor of ‘packing.’ This may include volunteer community brigades co-organized with VHTs, directly reducing the single most consistently cited barrier across all included studies.

Recommendation 3: Align IRS scheduling with local seasonal and agricultural calendars. Program planners should engage community and agricultural representatives during spray round planning to identify optimal scheduling windows that avoid peak agricultural seasons and rainy periods, thereby reducing the physical impossibility of outdoor preparation documented in Uganda and Tanzania.

Recommendation 4: Mandate VHT and traditional authority co-leadership of IRS campaigns. Given the strong evidence that trust is the primary mediator of IRS acceptance, programs should formally integrate Village Health Teams and traditional leaders into campaign governance, not merely as ‘mobilizers’ but as co-designers and co-implementers. This is supported by WHO guidelines on community engagement for vector control (2024) and the evidence from Uganda and Namibia in this review.

Recommendation 5: Develop differentiated behavior change communication for focal/reactive IRS strategies. As programs shift from mass campaigns to targeted or reactive focal vector control (RAVC), specific communication frameworks must explain the epidemiological rationale for spatial selection to prevent perceptions of political exclusion and spatial inequity, as documented in Namibia.

Strengths and limitations

A key limitation of this review is the small number of included studies (n = 10) and their uneven geographic distribution. Three studies were conducted in Mozambique and two in Uganda, while several high-burden countries such as Nigeria, the Democratic Republic of the Congo, Burkina Faso, and Mali were not represented. This reflects gaps in the primary literature rather than weaknesses in the review methodology and highlights the need for more qualitative IRS research in these settings.

The review was also restricted to English-language publications. Considering the extensive IRS programmes in Francophone West Africa and the presence of Swahili-language research in East Africa, relevant studies may have been missed. Future reviews should incorporate multilingual search strategies to reduce language bias.

A major strength of this review is the use of qualitative synthesis methods. By applying the SPIDER tool instead of traditional PICO frameworks, the review captured important socio-behavioral insights that are often overlooked in quantitative approaches. Integrating these findings with existing evidence on IRS effectiveness helps link community perspectives with public health outcomes.

This synthesis is limited by its reliance on self-reported data, which may be influenced by social desirability bias, especially in settings where IRS uptake is viewed as a civic responsibility or reinforced by local leaders. In addition, the diversity of cultural and political contexts across Sub-Saharan Africa limits the generalizability of the findings, as drivers of trust and mistrust are likely to vary between settings.

Conclusion

This systematic review of qualitative evidence successfully identified eight interdependent barriers and facilitators that determine community engagement with IRS in sub-Saharan Africa. The evidence confirms that the central barrier is not a lack of malaria knowledge but a complex intersection of disproportionate household labor burdens, toxicological fears, political distrust, gender inequities in domestic decision-making, and seasonal-operational misalignment. Conversely, the most powerful facilitators are community-embedded endorsement systems, specifically Village Health Teams and traditional authorities, as well as transparent, advance communication in local languages.

To address these issues, National Malaria Control Programs must urgently move beyond entomological coverage metrics and adopt human-centered implementation frameworks. Broad actions should include institutionalizing pre-spray community engagement, providing logistical support for vulnerable households, aligning spray schedules with local livelihood calendars, and embedding IRS within the permanent infrastructure of community health systems.

This review highlights important gaps in the existing evidence base. There is a notable geographic concentration of qualitative IRS studies in Mozambique and Uganda, with very limited evidence from high-burden countries such as Nigeria, the Democratic Republic of Congo, Burkina Faso, and Mali. Future primary qualitative studies are urgently needed in these settings, as well as mixed-methods studies that link community-defined barriers to quantitative coverage outcomes. Additionally, research specifically exploring the community experience of newer insecticide formulations and reactive focal spraying strategies represents a critical evidence gap.

Abbreviations

CASP

Critical Appraisal Skills Programme

ENTREQ

Enhancing Transparency in Reporting the Synthesis of Qualitative Research

FGDs

Focus group discussions

IDIs

In-depth interviews

IRS

Indoor residual spraying

KIIs

Key informant interviews

LLINs

Long-lasting insecticidal nets

MDA

Mass drug administration

PRISMA

Preferred reporting items for systematic reviews and meta-analyses

PROSPERO

International prospective register of systematic reviews

RAVC

Reactive focal vector control

SPIDER

Sample, Phenomenon of Interest, Design, Evaluation, Research Type

SSA

Sub-Saharan Africa

VHTs

Village Health Teams

WHO

World Health Organization

Author contributions

IP and PMO conceptualized the study, developed the methodology, and independently conducted the methodological quality appraisal of included studies. IP, PMO, LA, KVN, and PGA conducted the systematic search, screening, and data extraction. KCN, KDL, and KAO contributed to the thematic synthesis and drafting of the manuscript. All authors read and approved the final manuscript.

Funding

The authors declare that no funding was received for this study.

Availability of data and materials

The datasets generated and/or analyzed during the current systematic review are available from the corresponding author (Ivaan Pitua) on reasonable request.

Declarations

Ethics approval and consent to participate

Not applicable. As this study is a systematic review and qualitative evidence synthesis of previously published literature, it did not involve direct human subjects research and therefore did not require institutional ethics approval or consent to participate.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.