Emerg Infect DiseidEmerging Infectious Diseases1080-60401080-6059Centers for Disease Control106032212640808Research ArticleEffectiveness of pneumococcal polysaccharide vaccine for preschool-age children with chronic disease.FioreA. E.abf4@cdc.govLevineO. S.ElliottJ. A.FacklamR. R.ButlerJ. C.Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.Nov-Dec199956828831

To estimate the effectiveness of pneumococcal polysaccharide vaccine, we serotyped isolates submitted to the Pneumococcal Sentinel Surveillance System from 1984 to 1996 from 48 vaccinated and 125 unvaccinated children 2 to 5 years of age. Effectiveness against invasive disease caused by serotypes included in the vaccine was 63%. Effectiveness against serotypes in the polysaccharide vaccine but not in a proposed seven-valent protein conjugate vaccine was 94%.