Comparison 5. All vaccine types versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Influenza	9	8227	Risk Ratio (M‐H, Random, 95% CI)	0.30 [0.19, 0.45]
1.1 Live attenuated vaccines (1 dose)	5	3556	Risk Ratio (M‐H, Random, 95% CI)	0.33 [0.18, 0.62]
1.2 Live attenuated vaccines (2 doses)	2	3043	Risk Ratio (M‐H, Random, 95% CI)	0.11 [0.04, 0.26]
1.3 Inactivated vaccines (1 dose)	5	1628	Risk Ratio (M‐H, Random, 95% CI)	0.36 [0.28, 0.48]
1.4 Inactivated vaccines (2 doses)	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
2 Influenza‐like illness	8	143650	Risk Ratio (M‐H, Random, 95% CI)	0.69 [0.62, 0.77]
2.1 Live attenuated vaccines (1 dose)	2	3306	Risk Ratio (M‐H, Random, 95% CI)	0.64 [0.18, 2.22]
2.2 Live attenuated vaccines (2 doses)	6	121300	Risk Ratio (M‐H, Random, 95% CI)	0.66 [0.57, 0.76]
2.3 Inactivated vaccines (1 dose)	2	267	Risk Ratio (M‐H, Random, 95% CI)	0.35 [0.15, 0.81]
2.4 Inactivated vaccines (2 doses)	2	18777	Risk Ratio (M‐H, Random, 95% CI)	0.72 [0.69, 0.76]
3 Secondary cases	1	123	Risk Ratio (M‐H, Random, 95% CI)	1.68 [0.56, 4.99]
3.1 Live attenuated vaccines (1 dose)	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
3.2 Live attenuated vaccines (2 doses)	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
3.3 Inactivated vaccines (1 dose)	1	123	Risk Ratio (M‐H, Random, 95% CI)	1.68 [0.56, 4.99]
3.4 Inactivated vaccines (2 doses)	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
4 School absenteeism	1	550	Risk Ratio (M‐H, Random, 95% CI)	0.49 [0.26, 0.92]
4.1 Live attenuated vaccines (1 dose)	1	296	Risk Ratio (M‐H, Random, 95% CI)	0.51 [0.22, 1.19]
4.2 Live attenuated vaccines (2 doses)	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
4.3 Inactivated vaccines (1 dose)	1	254	Risk Ratio (M‐H, Random, 95% CI)	0.46 [0.17, 1.22]
4.4 Inactivated vaccines (2 doses)	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
5 Lower respiratory tract disease	2	1632	Risk Ratio (M‐H, Random, 95% CI)	0.20 [0.03, 1.54]
5.1 Live attenuated vaccines (1 dose)	2	1496	Risk Ratio (M‐H, Random, 95% CI)	0.16 [0.01, 4.45]
5.2 Live attenuated vaccines (2 doses)	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
5.3 Inactivated vaccines (1 dose)	1	136	Risk Ratio (M‐H, Random, 95% CI)	0.30 [0.01, 6.17]
5.4 Inactivated vaccines (2 doses)	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
6 Acute otitis media	6	5253	Risk Ratio (M‐H, Random, 95% CI)	1.00 [0.79, 1.26]
6.1 Live attenuated vaccines (1 dose)	3	2585	Risk Ratio (M‐H, Random, 95% CI)	0.42 [0.05, 3.79]
6.2 Live attenuated vaccines (2 doses)	1	1784	Risk Ratio (M‐H, Random, 95% CI)	0.98 [0.95, 1.01]
6.3 Inactivated vaccines (1 dose)	1	136	Risk Ratio (M‐H, Random, 95% CI)	1.52 [0.10, 23.76]
6.4 Inactivated vaccines (2 doses)	2	748	Risk Ratio (M‐H, Random, 95% CI)	1.15 [0.95, 1.40]
7 Hospitalisation due to acute otitis media	2		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
7.1 Inactivated vaccine (2 doses)	2	765	Risk Ratio (M‐H, Random, 95% CI)	1.41 [0.62, 3.24]
8 Consequences of acute otitis media	2		Mean Difference (IV, Random, 95% CI)	Subtotals only
8.1 Inactivated vaccine (2 (doses of the intervention) ‐ visits (outcome measure))	2	765	Mean Difference (IV, Random, 95% CI)	‐0.02 [‐0.27, 0.23]
8.2 Inactivated vaccine (2 doses; courses of antibiotics)	2	765	Mean Difference (IV, Random, 95% CI)	0.13 [‐0.36, 0.63]
9 Outpatients attendance for pneumonia and influenza	2	2874	Risk Ratio (M‐H, Random, 95% CI)	0.76 [0.59, 0.98]
9.1 Live attenuated vaccine (1 dose)	1	1090	Risk Ratio (M‐H, Random, 95% CI)	0.65 [0.49, 0.85]
9.2 Live attenuated vaccine (2 doses)	1	1784	Risk Ratio (M‐H, Random, 95% CI)	0.85 [0.75, 0.96]
10 Working days lost (number of events, parents of children 6 to 36 months of age)	2	2874	Risk Ratio (M‐H, Random, 95% CI)	0.69 [0.46, 1.03]
10.1 Live attenuated vaccine	2	2874	Risk Ratio (M‐H, Random, 95% CI)	0.69 [0.46, 1.03]
11 Drug prescriptions (number of events, 6 to 36 months of age)	1	1784	Risk Ratio (M‐H, Random, 95% CI)	0.99 [0.87, 1.12]
11.1 Live attenuated vaccine	1	1784	Risk Ratio (M‐H, Random, 95% CI)	0.99 [0.87, 1.12]