Department of Vaccination and Immune Protection, National Institute for Health and Welfare, FI-00271 Helsinki, Finland.
Epidemiol Infect. 2010 Jun;138(6):861-72. doi: 10.1017/S0950268809991415. Epub 2009 Dec 17.
The burden of pneumococcal carriage is largest in developing countries from which, however, detailed studies on pneumococcal transmission are missing. In this study we followed nasopharyngeal carriage in Bangladeshi infants (n=99) from birth, with 2-week sampling intervals until age 4 months, and monthly thereafter until age 1 year, and also their family members at the same intervals. We assessed the dependence of pneumococcal acquisition rates on age, serotype, serotype-specific exposure (i.e. transmission) and current state of carriage (yes/no). A statistical model of pneumococcal transmission, taking into account incompletely observed data, was applied to estimate rates of acquisition and clearance for a large number of serotypes at the same time. Serotypes that were common in the study population were more often acquired from the community than rarer serotypes. However, when conditioning on serotype-specific exposure within the family, transmission rates were similar between different serotypes. Exposure within families signified more than tenfold increase in the rate of acquisition.
肺炎球菌携带的负担在发展中国家最大，但这些国家缺乏对肺炎球菌传播的详细研究。在这项研究中，我们从出生开始对孟加拉国婴儿（n=99）的鼻咽携带情况进行了 2 周一次的采样，直到 4 个月大，此后每月一次，直到 1 岁。我们还在相同的间隔时间内对其家庭成员进行了采样。我们评估了肺炎球菌获得率对年龄、血清型、血清型特异性暴露（即传播）和当前携带状态（有/无）的依赖性。我们应用了一种考虑不完全观察数据的肺炎球菌传播统计模型，同时估计了大量血清型的获得和清除率。在研究人群中常见的血清型比罕见的血清型更容易从社区中获得。然而，当在家庭内对血清型特异性暴露进行条件化处理时，不同血清型之间的传播率相似。家庭内的暴露使获得率增加了十倍以上。
