Vaccination effects in patients or clients of HCW (the patient safety perspective)
| Review ID | Patient group | Laboratory-confirmed influenza | Clinically suspected influenza | Other statistically significant effects | Review authors’ conclusions | |||
|---|---|---|---|---|---|---|---|---|
| No. of studies (participants) | Efficacy (95% CI) | No. of studies (participants) | Efficacy | On efficacy | For policy | |||
| Burls et al13 | Those at risk. No further definition | Not reported | Not reported | Not reported | Not reported | Deaths from all-cause mortality, OR=0.56, p=0.0013 | ‘Vaccination was highly effective’* | ‘Effective implementation should be a priority’† |
| Michiels et al14 | No further definition | Refers to 2010 version of Thomas et al21 | No statistically significant effect | Refers to 2010 version of Thomas et al21 | No statistically significant effect | Deaths from all-cause mortality Effectiveness=34% (95% CI 21 to 45) | ‘There is little evidence that immunisation is effective in protecting patients’ | ‘Should not be mandatory at present’ |
| Ferroni and Jefferson16 | People aged at least 60 years in long-term care facilities | Two RCTs Refers to 2011 version of Thomas et al21 | No statistically significant effects | Refers to 2011 version of Thomas et al21 | 86% where some patients vaccinated to no significant effect where patients unvaccinated | Deaths from all-cause mortality, RR=0.66 (95% CI 0.55 to 0.79) (unadjusted) | ‘Influenza vaccination of healthcare workers and the older people in their care may be more effective at reducing influenza-like illness in older people living in institutions, although vaccination of healthcare workers alone may be no more effective’ | None stated |
| Ahmed et al22 | Patients in healthcare facilities. No further definition | Two RCTs (752) One observational study | RCTs—No statistically significant effects Observational study (≥35% vs <35% vaccinated HCWs)—adjusted OR=0.07 (0.01 to 0.98) | Three RCTs (7031) One observational study | RCTs—42% (95% CI 27 to 54) Observational study—no significant effect | Deaths from all-cause mortality, RR=0.71 (95% CI 0.59 to 0.85) | ‘Healthcare professional influenza vaccination can enhance patient safety’ | None stated |
| Dolan et al20 | At high risk of respiratory infection | Two RCTs (752), two observational studies (not stated) | RD 0.00 (−0.03 to 0.03) Observational studies found statistically significant effects | Three RCTs (not stated) Two observational studies (not stated) | RCTs and observational studies: statistically significant effects | Deaths from all-cause mortality, OR=0.68 (95% CI 0.55 to 0.84) (adjusted) | ‘A likely protective effect for patients’‡ | ‘The existing evidence base is sufficient to sustain current recommendations for vaccinating HCWs’ |
| Thomas et al21 | Aged >60 years living in institutions) | Two RCTs (752) | RD 0.00 (−0.03 to 0.03) | Not reported | Not reported | Not reported | ‘Did not identify a benefit of healthcare worker vaccination’† | ‘Does not provide reasonable evidence to support the vaccination of healthcare workers’ |
*Burns et al13 only present data on all-cause mortality from two cluster-RCTs. It reports that both trials found statistically significant effects but notes problems with the analysis in both trials.
†Thomas et al21 also report no statistically significant effects on hospitalisation or deaths due to lower respiratory tract infection. The authors chose not to present data on clinically suspected influenza or all-cause mortality as they doubt the validity of these measures when there is no effect on influenza.
‡This conclusion is based on statistically significant findings on clinically suspected influenza and all-cause mortality reported in an early version of Thomas et al21 but excluded from the most recent version of the review.20
HCW, healthcare worker; RCTs, randomised controlled trials; RD, risk difference; RR, relative risk.