Epidemiologic Implications of Asymptomatic Reinfection: A Mathematical Modeling Study of Norovirus
Epidemiologic Implications of Asymptomatic Reinfection: A Mathematical Modeling Study of Norovirus
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DOI：
10.1093/aje/kwt287
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发表时间：
2014-02-15
影响因子：
5
通讯作者：
Parashar, Umesh
中科院分区：
文献类型：
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作者：
Lopman, Ben;Simmons, Kirsten;Parashar, Umesh
诺瓦克病毒的致病性已经确定。然而，诺瓦克病毒经常在健康人的粪便中检测到。为了了解无症状感染的明显高流行率，我们分析了诺如病毒感染、疾病和免疫的动态传播模型。我们通过改变基本繁殖数（R-0）来模拟诺如病毒在低传播和高传播环境中的流行病学。我们预测了4岁至25岁低R-0和29岁高R-0儿童的年发病率值。然而，从低到高的R-0设置，无症状感染的点流行率从3急剧上升到48。在年龄较大的儿童和成人中，该模型预测，从低R-0到高R-0设置，疾病发病率将从6上升到16，而该年龄组的无症状感染患病率较低。诺如病毒的无症状流行率可随着R-0的微小变化而发生显著变化。在发达国家，病例患病率与对照患病率之比可能很高，在高接触环境中，尽管疾病发病率相似，但患病率接近甚至低于1。这些发现突出了病例对照研究的一个重要局限性，因为病原体的诊断特异性不够理想。
The pathogenicity of norovirus is definitively established. However, norovirus is frequently detected in the stool of healthy individuals. To gain understanding of the apparent high prevalence of asymptomatic infection, we analyzed a dynamic transmission model of norovirus infection, disease, and immunity. We simulated norovirus epidemiology in low- and high-transmission settings by varying the basic reproduction number (R-0). We predicted annual disease incidence values in children aged 04 years of 25 with a low R-0 and 29 with a high R-0. However, the point prevalence of asymptomatic infection rose sharply from 3 to 48 from the low to high R-0 settings. Among older children and adults, the models projected that incidence of disease would rise from 6 to 16 from the low to high R-0 settings, whereas asymptomatic infection prevalence was lower in this age group. Asymptomatic prevalence of norovirus can change dramatically with small changes in R-0. The ratio of prevalence in cases to controls could be high in a developed country and close to or even less than 1 in a high-exposure setting, despite similar disease incidence. These findings highlight an important limitation of case-control studies for pathogens for which there is suboptimal diagnostic specificity.