4. Sensitivity analysis for 'Summary of findings' table outcomes.
| Outcome (analysis) | All studies (primary analysis) | Studies at low risk of bias (sensitivity analysis) |
| Influenza (Analysis 1.1) | RR 0.41 (0.36 to 0.47) | RR 0.34 (0.25 to 0.45) |
| Influenza‐like illness (Analysis 1.2) | RR 0.84 (0.75 to 0.95) | RR 0.82 (0.69 to 0.98) |
| Hospitalisations (Analysis 1.8) | RR 0.96 (0.85 to 1.08) | RR 2.89 (0.12 to 70.68) |
| Fever (Analysis 1.11.2) | RR 1.55 (1.26 to 1.91) | RR 1.59 (1 to 2.53) |
| Nausea/vomiting (Analysis 1.11.5) | RR 1.80 (0.65 to 5.04) | RR 7.05 (1.61 to 30.87) |
RR: risk ratio