Abramson 2011

Methods	Purpose: to compare influenza vaccination uptake of those ≥ 65 attending primary care clinics which received an intervention to increase staff influenza vaccination uptake, or control (no staff intervention). No influenza intervention for patients Design: C‐RCT (intervention provided to staff in 13 intervention clinics and not provided in 14 control clinics) Duration of study: data extracted from HMO computers for 2007 to 2008 (intervention year) and previous year (2006 to 2007) Interval between intervention and when outcome was measured: 2007 to 2008 (intervention year) (no further details) Power computation: based on 2006 2007 imputed ICC = 0.019, for the sample of patients in 2007 to 2008 ≥ 65, alpha = 0.05, power = 80% for increase in vaccination uptake from 50% to 58%, and power of 90% for increase in vaccination uptake to 60% for the healthcare workers, based on previous year staff vaccination uptake, predicted 156 healthcare workers required in each of intervention and control groups for power = 90% to detect relative increase in staff immunisation from 30% to 50%, with alpha = 0.05 Statistics: odds ratios and 95% CI corrected for clustering, logistic regression
Participants	Country: Israel Setting: 27 primary care community clinics Eligible participants: (health status); all healthcare workers in the 13 intervention clinics; all patients ≥ 65 in 13 intervention and 14 control clinics Age: ≥ 65; staff were all 344 physicians, nurses, pharmacists, administrative and ancillary staff with direct patient contact Gender of patients: 58% f
Interventions	Intervention 1: intervention to increase staff influenza vaccination uptake in the Jerusalem area Control: no staff intervention Co‐interventions: none
Outcomes	Outcome measured: % ≥ 65 influenza vaccination (intervention clinics 2006 to 2007 avg influenza vaccination uptake 58.1% (43.4% 2006 to 2007); control 56.7% (44.7%). Data are from Table 1, text offers different %s Time points reported in the study: 2007 to 2008 was intervention year (time points not stated)
Notes	Funding: none stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Clinics randomly selected for staff intervention (method not stated)
Allocation concealment (selection bias)	Unclear risk	No statement
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No statement
Incomplete outcome data (attrition bias) All outcomes	Low risk	Baseline 11,755 in 13 intervention clinics; 420 (3.6%) excluded as died or left clinics or moved to sheltered accomodation before end of intervention period; 15,660 in 14 control clinics, 503 (3.2%) excluded
Selective reporting (reporting bias)	Low risk	No selective reporting