Vaccination effects on the health system (the employer perspective)
| Review ID | Population | Days off work | Review authors’ conclusions | ||
|---|---|---|---|---|---|
| No. of studies (participants) | Mean difference (days) | On efficacy | For policy | ||
| Ng and Lai12 | HCW | 2 (540) | –0.08 (95% CI –0.19 to 0.02) (third study not included in meta-analysis) | ‘No definitive conclusion on the effectiveness of influenza vaccinations in HCWs’ | ‘Further research is necessary to evaluate whether annual vaccination is a key measure to protect HCWs’ |
| Burls et al13 | HCW | 3 (967) | Statistically significant difference in only one of the three studies (MD 0.4 days, p=0.02) | ‘Vaccination was highly effective’ | ‘Effective implementation should be a priority’* |
| Demicheli et al19 | Healthy adults | 4 (3726) | Good match—three studies (2596), MD=−0.09 (−0.19 to 0.02) Matching absent/unknown—one study (1130), MD=0.09 (0.00 to 0.18) | ‘A modest effect on time off work’ | ‘No evidence for the usage of vaccination against influenza in healthy adults as a routine public health measure’† |
| Michiels et al14 | Healthy adults | Not stated | Not stated (refers to Jefferson 2010) | None stated | None stated |
| Ferroni and Jefferson16 | Healthy adults | 1 meta-analysis including 5 studies (5393) | Good match—0.21 Matching absent/unknown—0.09 (refers to Jefferson 2010) | ‘May be marginally more effective than placebo’ | None stated |
*This conclusion may be influenced by the reported effects on vaccine efficacy and protecting patients in tables 2 and 3, respectively.13
†This conclusion is influenced by the additional findings of no demonstrable effect on complications such as pneumonia or transmission.19
HCW, healthcare worker; MD, mean difference.