Prevention of Pneumococcal Infection With Vaccines: An Evolving Story

摘要: THE FIRST VACCINES TO PREVENT PNEUMOCOCCAL INfections, crude preparations of killed bacteria, were developed by Sir Almroth Wright in 1911 to try alleviate the high mortality and morbidity among gold miners South Africa. Discovery that antibodies against purified polysaccharides capsular surface pneumococci protective led development polysaccharide vaccines marketed 1940s. These commercial failures because advent antimicrobials a perception pneumococcal infections no longer major threat. Subsequent evidence persistence significant from infections, as well rates 25% 30% patients with invasive (including bacteremic) despite early treatment antimicrobials, redevelopment vaccine, approved United States 1977, contained 14 more than 90 serotypes (responsible for about 80% States). In 1983 current expanded formulation vaccine contains 23 (PPSV23) was introduced. Current recommendations are immunization persons 2 years older conditions put them at increased risk serious all 65 PPSV23. Although there is good PPSV23 has least moderate effectiveness preventing its nonbacteremic pneumonia (NPP) appears be poor. Compared bacteremic pneumonia, adults NPP thought 10 times common responsible considerably mortality. Children younger used have highest incidence infections. Polysaccharides, which composed, T-cell–independent immunogens poor immunogenicity young children. However, bonding (conjugating) certain proteins, conjugated antigens processed T-cell–dependent even infants an effective immunologic response. addition, protein-polysaccharide conjugate induce memory associated anamnestic (booster) antibody responses upon reexposure likely provide longer-lasting immunity vaccines. The success Haemophilus influenzae type b, formerly most cause bacterial meningitis but virtually eliminated since introduction this 1988, encouraged pneumococci. 2000, 7-valent pneumococcus (PCV7) introduced routine childhood immunization. reducing disease included much smaller still increase caused some not PCV7 (notably serotype 19A). 2010, replaced includes 13 (PCV13) expected further reduce Food Drug Administration recently PCV13 use adults. Work continues on based other shared by, presumably could protection against, issue JAMA, Smith colleagues report substitution would cost-effective per qualityadjusted life-year (QALY) gained (ie, $28 900/QALY compared $34 000/QALY gained), consistent similar analyses conducted Europe. single