Twelve randomised studies (n=45,226) were included in the review . Three reported outcomes in healthy people (n=21,152) and ten reported outcomes in people likely to be immunocompromised (n=24,074).
All pneumoniae.
Vaccination significantly reduced the risk of pneumonia in immunocompetent people (3 trials; RR 0.56, 95% CI: 0.47, 0.66; NNT 29, 95% CI: 24, 36). There was no significant effect of vaccination on the rates of pneumonia in elderly or high-risk people (5 trials; RR 1.08, 95% CI: 0.92, 1.27).
Pneumococcal pneumonia.
Vaccination significantly reduced the risk of pneumococcal pneumonia in immunocompetent people (3 trials; RR 0.16, 95% CI: 0.11, 0.23; NNT 38, 95% CI: 33, 45). There was no significant effect of vaccination on the rates of pneumococcal pneumonia in elderly or high-risk people (7 trials; RR 0.88, 95% CI: 0.72, 1.07).
Lower respiratory tract infections.
There was no significant effect of vaccination on the rates of lower respiratory tract infection in immunocompetent people (2 trials; RR 0.85, 95% CI: 0.71, 1.02) or elderly or high-risk people (3 trials; RR 1.06, 95% CI: 0.97, 1.16).
Pneumonia-related deaths.
Vaccination significantly reduced the risk of pneumonia-related death in immunocompetent people (1 trial; RR 0.70, 95% CI: 0.50, 0.96; NNT 213, 95% CI: 114, 1,660). There was no significant effect of vaccination on the rates of pneumonia-related death in elderly or high-risk people (8 trials; RR 0.93, 95% CI: 0.72, 1.20).
Pneumococcal bacteraemia.
Vaccination significantly reduced the risk of pneumococcal bacteraemia in immunocompetent people (1 trial; RR 0.18, 95% CI: 0.09, 0.34; NNT 32, 95% CI: 26, 44). There was no significant effect of vaccination on the rates of pneumococcal bacteraemia in elderly or high risk people (3 trials; RR 0.53, 95% CI: 0.14, 1.94).