Efficacy of Pneumococcal Polysaccharide Vaccines

Trials to determine efficacy of pneumococcal vaccine prior to its licensure resulted in estimates of efficacy of 76010-100010. However, the populations studied in these trials were dissimilar to the population in this country at high risk of morbidity and mortality due to pneumococcal infection. Estimates based on data obtained in this country after licensure of the vaccine suggest that the efficacy in certain groups may be low: ~OOJo in children two to 10 years of age and 49010 (95010 confidence interval, ~OOJo-75OJo) in per-sons older than 10 years of age. In the three years since relicensure of the pneumo-coccal vaccine, recommendations by individual physicians and by departments of public health for its use in this country have been somewhat ten-tative [1]. The data required before more defini-tive recommendations can be made include those on the efficacy of the vaccine in the target groups, i.e., the percentage reduction in rate of vaccine-