Potter 1997.

Methods	Purpose: to assess the effect of staff and patient vaccination against influenza in residents Serologically proven influenza ILI Lower respiratory tract infection Deaths (from all causes) Deaths (from pneumonia) Design: 6 geriatric long‐stay hospitals in Glasgow in 1994 had an "opt‐out" policy in which patients were routinely given influenza vaccine unless they refused it or had a major contraindication and 6 had an "opt‐in" policy in which patients were given vaccine only if they or their relatives requested it following advertisement on the ward that it was available Hospitals were stratified by policy on vaccination then randomised for their HCWs to be "routinely offered either influenza vaccination or no vaccination." Study conducted in Scotland, during the 1994 to 1995 influenza season, in the community. Follow‐up period was 1 October 1994 to 31 March 1995. 12 hospitals were randomly allocated to offer vaccination of HCWs or not; facilities were grouped according to the vaccination policy. The vaccination of staff and patients was voluntary. The study thus presents data on 4 sub‐populations: ‐ staff and patients not vaccinated (S0P0) ‐ staff not vaccinated, patients vaccinated (S0PV) ‐ staff and patients vaccinated (SVPV) ‐ staff vaccinated and patients not vaccinated (SVP0) Statistical analysis: "Baseline characteristics, morbidity and mortality in the 4 groups of hospitals were compared using the X2 test, unpaired Student's test and Wilcoxon rank sum test as appropriate. Odds ratios and 95% CIs were calculated for the effects of staff and patient vaccination. Survival analysis was by Kaplan‐Meier product limit estimates, using the Tarone Ware test for statistical significance. Cluster analysis, examining mortality rates and other outcomes by hospital site, was also done."
Participants	Country: Scotland Setting: 12 geriatric medical long‐term care hospitals in Glasgow Eligible participants: 1059 hospital residents. All 1078 HCWs (day and night nurses and nursing auxiliaries, ward cleaners, doctors, therapists and porters) in SVPV and SVP0 hospitals were offered vaccination but "voluntary workers, patients' friends and relatives and other casual or occasional ward visitors were not offered vaccine." Observed units were hospitals and not patients 654 (61%) of the 1078 agreed to participate; vaccination was contraindicated in 34 (3%) and 47 (4%) were on long‐term sick leave and unavailable The physical dependency level of patients was measured on the 20‐point Barthel scale. The hospitals where patients were routinely offered vaccination (S0PV and SVPV) had lower Bartel scores (P value = 0.003) than those not offered vaccination but there were no differences between hospitals where HCWs were vaccinated and those where they were not Age: 77 Gender: 71% F
Interventions	Vaccination of patients and HCWs began October 1994 ("4 weeks before the earliest likely start date of the annual influenza outbreak"). Parenteral influenza vaccine. Vaccine strains probably matched the circulating strain
Outcomes	Serologically proven influenza (paired sera in 225 consenting patients in the "patients not vaccinated" arms) ILI (defined as a temperature of ≥ 37°C, "plus one of the following symptoms: new‐onset cough, coryza, sore throat, malaise, headache, or muscle aches" ‐ reported singly or within the ILI outcome) and was monitored from the end of October 1994 to the end of March 1995 LRTI ("was identified by the presence of (1) pulmonary crackles, wheeze or tachypnoea plus temp ≥ 37 °C or WBC > 10 x 109/L or (2) a positive sputum culture" and was monitored from the end of October 1994 to the end of March 1995 Deaths (from all causes) Deaths (from pneumonia) All deaths and discharges and admissions to the wards were recorded Ward staff notified the research nurse of any patient who developed clinical symptoms of upper respiratory tract viral illness, influenza or lower respiratory tract infection and the research nurse visited the patient within 24 hours to record symptoms, clinical signs and investigations on standardised forms. "Chest radiographs were not included as part of the routine assessment of suspected lower respiratory tract infection, as for many of the peripheral hospitals, it would have required an ambulance journey for the patient." "Patients with suspected viral illness who gave verbal consent had a nasopharyngeal aspirate (NPA) sample obtained within 48 hours of notification of symptoms. IFA for influenza A and B, respiratory syncytial virus (RSV), Chlamydia psittaci and adenovirus antigens" were obtained Antibody levels to Mycoplasma pneumoniae (M. pneumoniae) were ascertained by complement fixation in consenting patients who had not received influenza vaccination
Notes	Staff vaccination was incomplete and variable; results were presented by hospital group and not by vaccination status of patients. The authors concluded that vaccination of HCWs was associated with lower mortality and ILI. These benefits were not evident vaccinating patients alone Mean cluster size: 88 (based on data for mortality outcomes) Intra‐cluster variance of 2.3% reported in Hayward 2006
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Hospital sites were stratified by unit policy for vaccination, then randomised for their HCWs to be routinely offered either influenza vaccination and their patients unvaccinated (S0P0), staff vaccinated and patients unvaccinated (SVP0), staff unvaccinated and patients vaccinated (S0PV) and both staff and patients vaccinated (SVPV)" (N.B. the phrase "either influenza vaccination and their patients unvaccinated (S0P0)" is an error and should read: "neither staff nor patients vaccinated (S0P0)")
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	High risk	Only 654 (61%) of the 1078 HCWs agreed to participate and receive influenza vaccination and 478 (88.8%) of the 538 patients in the "routine vaccination of patients" arms. Serologically proven influenza was ascertained in paired sera in only 225 consenting patients in the "patients not vaccinated" arms
Selective reporting (reporting bias)	Low risk	No selective reporting
Other bias	High risk	Selection bias: the total number of long‐term care hospitals in West and Central Scotland is not stated. There were inconsistencies in outcome gradients (see Table 2). In the population under observation, Potter 1997 reported 216 cases of suspected viral illness, 64 cases of ILI, 55 cases of pneumonia, 72 deaths from pneumonia and 148 deaths from all causes; in the sub‐population of both vaccinated staff and patients, Potter 1997 reported 24 cases of suspected viral illness, 2 cases of ILI, 7 cases of pneumonia, 10 deaths from pneumonia and 25 deaths from all causes. As these gradients are not plausible, the effect on all‐cause mortality is likely to reflect a selection bias rather than a real effect of vaccination Performance bias: 67% of staff in active arm 1 and 43% in active arm 2 were vaccinated There is no description of the vaccines administered, vaccine matching or background influenza epidemiology

Avg: average
 C‐RCT: cluster‐randomised controlled trial
 F: female
 HCWs: healthcare workers
 ILI: influenza‐like illness
 LRTI: lower respiratory tract infection
 LTC: long‐term care
 PCR: polymerase chain reaction
 RCT: randomised controlled trial
 RT‐PCR: reverse‐transcriptase polymerase chain reaction
 S0P0: staff and patients not vaccinated
 S0PV: staff not vaccinated, patients vaccinated
 SVPV: staff and patients vaccinated
 SVP0: staff vaccinated and patients not vaccinated
 WBC: white blood cell