Hayward 2006.

Methods	Purpose: to increase staff vaccination rates in care homes by adoption of a policy to encourage staff to be vaccinated against influenza and providing vaccination clinics Design: C‐RCT; 48 nursing homes were placed in matched pairs (by size of home, % of high dependency and mortality of residents) within 3 regions (northern, central and southern England), then the 25 homes that most closely matched were selected and randomised by a researcher, blinded to the home's identity and characteristics, using a table of random numbers. Data from the Royal College of General Practitioners sentinel surveillance scheme were used to divide the study into periods of influenza activity and no influenza activity Duration of study: 3 November 2003 to 28 March 2004 and 1 November 2004 to 27 March 2005 Interval between intervention and when outcome was measured: 3 November 2003 to 28 March 2004 and 1 November 2004 to 27 March 2005 Power computation: to detect reduction in all‐cause mortality of residents from 15% to 10% (intra‐cluster variance = 2.3%) with 90% power and alpha = 0.05% level required 20 pairs of homes each with an average of 20 residents (based on findings from pilot study) Statistics: outcomes were analysed using aggregate data for each cluster and "to take account of the matched clustered design we used a random‐effects meta‐analysis. This treated the results from each pair of homes as a separate study and provided a pooled estimate of effect weighted for the size of homes and the size of the effects and their standard errors." "When significant protection of residents was observed we calculated the number of staff vaccinations needed to prevent one event in residents (number needed to treat) as number of vaccinations given in all intervention homes divided by the average number of residents in all intervention homes multiplied by the weighted rate difference."
Participants	Country: UK Setting: private chain of nursing homes, whose policy was not to offer influenza vaccination to staff Eligible participants: (health status): 1 intervention and 1 control home were unable to provide data so they and their matched home were excluded, leaving 44 homes for analysis; eligible staff were all staff in intervention homes (full‐time: n = 844 in both 2003 to 2004 and in 2004 to 2005) and (part‐time: n = 766 in 2003 to 2004 and n = 882 in 2004 to 2005) Age: Avg 83 Gender: 71% F
Interventions	Intervention 1: Adoption of policy in intervention homes of vaccinating staff against influenza, including a lead nurse in each home was trained to promote vaccination of staff; distribute leaflets and posters and liaise to provide 3 vaccination clinics for staff in each home. Staff were sent a letter explaining the study and the potential benefits of influenza vaccination Control: staff in control homes received a letter describing the study and the Department of Health recommendation that those with chronic illnesses should receive influenza vaccination No attempt to influence vaccination of residents in any home
Outcomes	Primary outcome of the study: to assess effect of vaccinating staff on all‐cause mortality of residents Secondary outcomes: ILI (defined as fever 37.8°C measured orally, or an acute deterioration in physical or mental ability, plus either new onset or one or more respiratory symptoms or an acute worsening of a chronic condition involving respiratory symptoms), mortality with ILI, admission to hospital from any cause, admission to hospital with ILI and consultations with a GP for ILI Other outcomes measured: % of staff vaccinated Time points from the study that are considered in the review or measured or reported in the study: 3 November 2003 to 28 March 2004 and 1 November 2004 to 27 March 2005 % of staff vaccinated: by 28 March 2004 for first year of study and by 27 March 2005 for second year of study: full‐time staff: intervention group 407/844 vaccinated; control group 51/859 Part‐time staff: intervention group 163/766 vaccinated; control group 33/815
Notes	Funding: UK Department of Health Mean cluster size: 71 Intra‐cluster correlation coefficient: 0.023 Vaccine content was not reported. No conclusions on matching can be drawn
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"A researcher blinded to the home’s identity and characteristics carried out randomisation within those pairs using random number tables."
Allocation concealment (selection bias)	Low risk	"A researcher blinded to the home’s identity and characteristics carried out randomisation."
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No statement
Incomplete outcome data (attrition bias) All outcomes	High risk	"No outcome data were available for the excluded homes so an intention to treat analysis was not possible."
Selective reporting (reporting bias)	Unclear risk	Although the study does not contribute data for relevant outcomes we are unable to ascertain whether influenza‐specific outcome data were collected and analysed
Other bias	Low risk	No other issues were identified