基于年龄结构的中国麻疹传播动态的分析

Measles Transmission Dynamics in China Based on Age-Structure Model

分析中国麻疹不同年龄的被感染风险及传染率的季节性,并分析了儿童间周期性接触及整体人群的周期性接触如何形成我国麻疹传染率的季节性。根据中国20132016年麻疹分年龄组的数据,应用感染力分析模型,估算了中国麻疹不同年龄的感染力(即被感染风险);建立了基于年龄结构的具有季节性传染率的时间序列易感者感染者恢复者(time series susceptible-infected-recovered,TSIR)模型,并对中国麻疹的传播动态进行分析。模型包含了两种不同的传染率季节性驱动因素:儿童间的周期性接触率、整体人群的周期性接触率,研究了开学放假和春运引起的接触率变化对传染率季节性的影响。结果表明:1)中国麻疹不同年龄的感染力不同,其中<1岁的婴儿感染力最高为24%-44%,其次是5065岁人群;2)由学期和春运引起的两种周期性接触率都会导致麻疹传染率的季节性,其中开学期间传染率较均值增加31%;3)由春运引起的整体人群接触率的季节性导致春运期间传染率较均值增加23%。

This paper aims to analyze the force of infection of measles and the seasonality of measles transmission rate at different age groups in China,and to analyze the effect of seasonal children’s contact rate and seasonal population’s contacts on the seasonality of measles transmission rate.Base on the age-stratified reported cases of measles in China from 2013 to 2016,we used the force of infection analysis model to estimate the age-specific force of infection;we established an age-structured time series susceptible-infected-recovered(TSIR)model and analyzed the transmission dynamics of measles in China.The model contains two different driving factors for the measles seasonal transmission:the periodic contact rate among children,and the periodic contact rate of the overall population.Our results show that:1)the force of infection of measles in China varied across ages with the highest for infants less than one years old(24%44%)and the second highest for people aged 5065 years;2)Seasonal contact rates that due to both school terms and Spring Festival travel rush will lead to seasonal transmission rate of measles in China;3)school terms can increase transmission rate by 31%,and seasonal population contact rate caused by Spring Festival travel rush can increase the transmission rate by 23%.