Coen P G, Heath P T, Barbour M L, Garnett G P
Wellcome Trust for Epidemiology and Infectious Disease, Zoology Department, Oxford University.
Epidemiol Infect. 1998 Jun;120(3):281-95. doi: 10.1017/s0950268898008784.
A review of empirical studies and the development of a simple theoretical framework are used to explore the relationship between Haemophilus influenzae type b (Hib) carriage and disease within populations. The models emphasize the distinction between asymptomatic and symptomatic infection. Maximum likelihood methods are used to estimate parameter values of the models and to evaluate whether models of infection and disease are satisfactory. The low incidence of carriage suggests that persistence of infection is only compatible with the absence of acquired immunity to asymptomatic infection. The slight decline in carriage rates amongst adults is compatible with acquired immunity, but could be a consequence of reduced contacts. The low rate of disease observed in adulthood cannot be explained if protection from disease is a product of previous detectable exposure to Hib alone. We estimate an R0 of 3.3 for Hib in developed countries, which suggests that current immunization programmes may eliminate the infection. Analysis of the disease data set suggests the absence of maternal immunity and increased susceptibility to disease in the oldest age classes.
通过对实证研究的回顾以及构建一个简单的理论框架，来探讨人群中b型流感嗜血杆菌（Hib）携带与疾病之间的关系。这些模型强调了无症状感染和有症状感染之间的区别。使用最大似然法来估计模型的参数值，并评估感染和疾病模型是否令人满意。携带率较低表明，感染的持续仅与缺乏针对无症状感染的获得性免疫相容。成年人中携带率的轻微下降与获得性免疫相符，但也可能是接触减少的结果。如果仅通过先前可检测到的Hib暴露来预防疾病，那么在成年期观察到的低疾病发生率就无法解释。我们估计发达国家中Hib的R0为3.3，这表明当前的免疫计划可能会消除这种感染。对疾病数据集的分析表明，缺乏母体免疫，且最年长者对疾病的易感性增加。
