Comparison 1. Palivizumab versus placebo or no intervention.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 Hospitalisation due to RSV infection	5	3343	Risk Ratio (M‐H, Random, 95% CI)	0.44 [0.30, 0.64]
1.2 Mortality	5	3343	Risk Ratio (M‐H, Random, 95% CI)	0.69 [0.42, 1.15]
1.3 Adverse events	3	2831	Risk Ratio (M‐H, Random, 95% CI)	1.09 [0.85, 1.39]
1.4 Hospitalisation due to respiratory‐related illness	5	3343	Risk Ratio (M‐H, Random, 95% CI)	0.78 [0.62, 0.97]
1.5 Subgroup analysis: hospitalisation due to respiratory‐related illness	5	3343	Risk Ratio (M‐H, Random, 95% CI)	0.78 [0.62, 0.97]
1.5.1 High‐income countries	4	3260	Risk Ratio (M‐H, Random, 95% CI)	0.80 [0.65, 0.99]
1.5.2 Low‐ and middle‐income countries	1	83	Risk Ratio (M‐H, Random, 95% CI)	0.47 [0.18, 1.22]
1.6 Length of hospital stay	2	2789	Mean Difference (IV, Random, 95% CI)	‐42.24 [‐84.77, 0.29]
1.7 RSV infection	3	554	Risk Ratio (M‐H, Random, 95% CI)	0.33 [0.20, 0.55]
1.8 Number of wheezing days	1	429	Risk Ratio (IV, Random, 95% CI)	0.39 [0.35, 0.44]
1.9 Days of supplemental oxygen	2	2789	Mean Difference (IV, Random, 95% CI)	‐36.85 [‐85.19, 11.49]
1.10 Intensive care unit length of stay	2	2789	Mean Difference (IV, Random, 95% CI)	‐13.51 [‐61.11, 34.08]
1.11 Mechanical ventilation days	2	2789	Mean Difference (IV, Random, 95% CI)	5.78 [‐10.37, 21.92]