Pneumococcal polysaccharide vaccine: a systematic review of clinical effectiveness in adults.

UNLABELLED Pneumococcal polysaccharide vaccine is recommended in western countries for individuals at high risk of pneumococcal illness. We undertook a systematic review of randomised controlled trials of pneumococcal vaccine in adults, to determine the effects on clinical outcomes. RESULTS In industrialised populations, no benefit was detected for outcomes other than pneumococcal bacteraemia, and this did not reach statistical significance. In non-industrial populations, clear benefit was demonstrated for mortality and all-cause pneumonia. CONCLUSION Benefit from pneumococcal vaccination depends on the baseline risk of infection and characteristics of a given population. Evidence from randomised trials for widespread adult vaccination in industrial countries is lacking.