Comparison 17. 1968 to 1969 pandemic: live aerosol influenza vaccine versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Influenza cases (clinically defined without clear definition)	1	19887	Risk Ratio (M‐H, Random, 95% CI)	0.98 [0.92, 1.05]
1.1 Non‐matching	1	19887	Risk Ratio (M‐H, Random, 95% CI)	0.98 [0.92, 1.05]
2 Complications (bronchitis, otitis, pneumonia)	1	19887	Risk Ratio (M‐H, Random, 95% CI)	0.25 [0.03, 2.24]
2.1 Non‐matching	1	19887	Risk Ratio (M‐H, Random, 95% CI)	0.25 [0.03, 2.24]