Summary of findings for the main comparison. Summary of findings table.
| Healthcare workers offered influenza vaccination compared with no vaccination: effects on influenza outcomes in people aged over 60 living in long‐term care institutions | ||||||
| Patient or population: People aged 60 or older living in long‐term care institutions Setting: Europe. Studies were conducted during influenza seasons (data from periods of high influenza activity) Intervention: HCWs offered vaccination Comparison: HCWs not offered vaccination | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Risk difference (95% CI) | N of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk in people living in care institutions where HCWs not offered influenza vaccination | Risk in people living in care institutions where HCWs offered influenza vaccination | |||||
| Influenza Follow‐up to end of influenza season |
Study population | 0 (‐0.03 to 0.03) | 752 (2 studies) | ⊕⊕⊝⊝ LOW 1 2 | ||
| 5 per 100 |
5 per 100 (2 to 8) |
|||||
| Lower respiratory tract infection Follow‐up to end of influenza season |
Study population | ‐0.02 (‐0.04 to 0.01) | 1059 (1 study) | ⊕⊕⊕⊝ MODERATE 1 | ||
| 6 per 100 | 4 per 100 (2 to 7) | |||||
| Admission to hospital for respiratory illness Follow‐up to end of influenza season |
Study population | 0 (‐0.02 to 0.02) | 3400 (1 study) | ⊕⊕⊝⊝ LOW 1 2 | ||
| 9 per 100 | 9 per 100 (7 to 11) | |||||
| Deaths from influenza or its complications Follow‐up to end of influenza season |
The results of the studies differed substantially. We did not combine data due to the inconsistency of the size and direction of the trial risk differences The risk of death from influenza or pneumonia was 1% and 8% in the control arms of the studies. The risk of death in the HCW vaccination arms was 5% and 1% in the two studies. | Not pooled | 4459 (2 studies) | ⊕⊝⊝⊝ VERY LOW 3 4 | ||
| Deaths from all causes | The results of the studies differed substantially. We did not combine data due to the inconsistency of the size and direction of the trial risk differences. The risk of death from any cause ranged from 6% to 22% in the control groups. The risk of death in the HCW vaccination arms ranged from 5% to 13%. | Not pooled | 8468 (4 studies) |
⊕⊝⊝⊝ VERY LOW 3 4 | ||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the risk difference of the intervention (and its 95% CI) CI: confidence interval;HCW: healthcare worker | ||||||
| GRADE Working Group grades of evidence High quality: We are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low quality: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect | ||||||
1Downgraded one level due to serious risk of bias: high risk of performance/detection bias.
2Downgraded one level due to serious imprecision: confidence interval includes clinically important differences with either intervention.
3Downgraded two levels due to very serious inconsistency: meta‐analysis was not undertaken for this outcome in view of the high levels of statistical heterogeneity for this outcome and variation in the direction of the effect across the studies,.
4 Downgraded one level due to serious risk of bias: high risk of attrition bias.