Park In H, Moore Matthew R, Treanor John J, Pelton Stephen I, Pilishvili Tamara, Beall Bernard, Shelly Mark A, Mahon Barbara E, Nahm Moon H
Departments of Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
J Infect Dis. 2008 Dec 15;198(12):1818-22. doi: 10.1086/593339.
Because classic pneumococcal serotyping methods cannot distinguish between serotypes 6A and 6C, the effects of pneumococcal vaccines against serotype 6C are unknown. Pneumococcal vaccines contain serotype 6B but not serotypes 6A and 6C.
We used a phagocytic killing assay to estimate the immunogenicity of the 7-valent conjugate vaccine (PCV7) in children and the 23-valent polysaccharide vaccine (PPV23) in adults against serotypes 6A and 6C. We evaluated trends in invasive pneumococcal disease (IPD) caused by serotypes 6A and 6C in the United States, using active surveillance.
Serum specimens from PCV7-immunized children had median opsonization indices of 150 and < 20 for serotypes 6A and 6C, respectively. Similarly, only 52% of adults (25 of 48) vaccinated with PPV23 showed opsonic indices of > 20 against serotype 6C. During 1999--2006, the incidence of serotype 6A IPD decreased by 91% (from 4.9 to 0.46 cases per 100,000 persons; P < .05) among individuals aged < 5 years and by 58% (from 0.86 to 0.36 cases per 100,000 persons; P < .05) among those aged > or = 5 years. Although the incidence of 6C IPD showed no consistent trend (range, 0-0.6 cases per 100,000 persons) among individuals aged < 5 years, it increased from 0.25 to 0.62 cases per 100,000 persons (P < .05) among those aged > or = 5 years.
PCV7 introduction has led to reductions in serotype 6A IPD but not serotype 6C IPD in the United States.
由于传统的肺炎球菌血清分型方法无法区分6A和6C血清型，因此肺炎球菌疫苗针对6C血清型的效果尚不清楚。肺炎球菌疫苗包含6B血清型，但不包含6A和6C血清型。
我们使用吞噬杀伤试验评估7价结合疫苗（PCV7）对儿童以及23价多糖疫苗（PPV23）对成人针对6A和6C血清型的免疫原性。我们通过主动监测评估美国由6A和6C血清型引起的侵袭性肺炎球菌疾病（IPD）的趋势。
PCV7免疫儿童的血清标本中，6A和6C血清型的调理指数中位数分别为150和<20。同样，接种PPV23的成人中，只有52%（48人中的25人）针对6C血清型的调理指数>20。在1999 - 2006年期间，5岁以下个体中6A血清型IPD的发病率下降了91%（从每10万人4.9例降至0.46例；P<.05），5岁及以上个体中下降了58%（从每10万人0.86例降至0.36例；P<.05）。尽管5岁以下个体中6C血清型IPD的发病率没有一致的趋势（范围为每10万人0 - 0.6例），但5岁及以上个体中其发病率从每10万人0.25例增加至0.62例（P<.05）。
在美国，引入PCV7已导致6A血清型IPD减少，但6C血清型IPD未减少。
