Table 5

Vaccination effects in patients or clients of HCW (the patient safety perspective)

Review IDPatient groupLaboratory-confirmed influenzaClinically suspected influenzaOther statistically significant effectsReview authors’ conclusions
No. of studies (participants)Efficacy (95% CI)No. of studies (participants)EfficacyOn efficacyFor policy
Burls et al13Those at risk. No further definitionNot reportedNot reportedNot reportedNot reportedDeaths from all-cause mortality, OR=0.56, p=0.0013‘Vaccination was highly effective’*‘Effective implementation should be a priority’†
Michiels et al14No further definitionRefers to 2010 version of Thomas et al21No statistically significant effectRefers to 2010 version of Thomas et al21No statistically significant effectDeaths 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 Jefferson16People aged at least 60 years in long-term care facilitiesTwo RCTs
Refers to 2011 version of Thomas et al21
No statistically significant effectsRefers to 2011 version of Thomas et al2186% where some patients vaccinated to no significant effect where patients unvaccinatedDeaths 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 al22Patients in healthcare facilities. No further definitionTwo 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 al20At high risk of respiratory infectionTwo 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 effectsDeaths 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 al21Aged >60 years living in institutions)Two RCTs (752)RD 0.00 (−0.03 to 0.03)Not reportedNot reportedNot 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.