Comparison 8. Inactivated vaccines (cohort studies by age group).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Influenza	6	1873	Risk Ratio (M‐H, Random, 95% CI)	0.42 [0.25, 0.73]
1.1 under 2 years	3	314	Risk Ratio (M‐H, Random, 95% CI)	0.63 [0.27, 1.47]
1.2 under 6 years	1	180	Risk Ratio (M‐H, Random, 95% CI)	0.34 [0.13, 0.89]
1.3 over 6 years	2	1379	Risk Ratio (M‐H, Random, 95% CI)	0.36 [0.12, 1.11]
2 Influenza‐like illness	11	11935	Risk Ratio (M‐H, Random, 95% CI)	0.53 [0.42, 0.67]
2.1 under 2 years	1	23	Risk Ratio (M‐H, Random, 95% CI)	0.47 [0.23, 0.93]
2.2 under 6 years	5	7046	Risk Ratio (M‐H, Random, 95% CI)	0.74 [0.59, 0.93]
2.3 over 6 years	7	4866	Risk Ratio (M‐H, Random, 95% CI)	0.44 [0.29, 0.68]
3 Otitis media	1	119	Risk Ratio (M‐H, Random, 95% CI)	0.48 [0.22, 1.03]
3.1 Children aged 6 months to 5 years	1	119	Risk Ratio (M‐H, Random, 95% CI)	0.48 [0.22, 1.03]