Clinical effectiveness of pneumococcal vaccine. Meta-analysis.

OBJECTIVE To determine the clinical effectiveness of pneumococcal vaccine. DATA SOURCES Computerized searches of MEDLINE, EMBASE, and SCISEARCH databases were performed, reference lists of retrieved articles were reviewed, and first authors of published studies were contacted. STUDY SELECTION Studies of use of pneumococcal vaccines in adults were included if the study design was a randomized or quasi-randomized controlled trial and at least one of the following clinical outcomes was reported: vaccine-type systemic pneumococcal infection, systemic pneumococcal infection, vaccine-type pneumococcal pneumonia, pneumococcal pneumonia, non-vaccine-type pneumococcal pneumonia. SYNTHESIS Study quality was assessed and descriptive information concerning the study populations, interventions, and outcome measurements was extracted for 13 trials involving more than 65,000 patients. Estimates of vaccine efficacy, based on a meta-analysis of randomized and quasi-randomized trials, were determined for clinical outcomes. CONCLUSIONS Vaccination with pneumococcal polysaccharide vaccine can be expected to reduce the risk of systemic infection due to pneumococcal types included in the vaccine by 83% and systemic infection due to all pneumococci by 73%. We found no evidence that the vaccine was less efficacious for the elderly, institutionalized people, or those with chronic disease.