REVIEW Pneumococcal Vaccine: Clinical Efficacy and Effectiveness

Streptococcus pneumoniae causes substantial morbidity and mortality. Incidence and severity are increased among populations with some chronic diseases. The currently available polyvalent polysaccharide vaccine induces antibody production among immunologically competent recipients against the 14 serotypes responsible for 80 % of pneumococcal bacteremia in the United States. The vaccine is safe and has proved efficacious in clinical trials with healthy young men in epidemic conditions and in patients with sickle cell anemia. Similar trials in two other high-risk populations had inconclusive results. Decisions on vaccine use now largely rest on indirect evidence of efficacy derived from knowledge of disease incidence, severity, and antibody response to vaccination among patient groups. Finding