Analysis Of Measles Epidemic Characteristics Based On Age Structure

Measles is a highly contagious respiratory infection caused by the measles virus.Although the immunization rate of measles in China has reached a fairly high level(99%),it is still one of the countries with the highest incidence in the world.The task of eliminating measles is still arduous,so research on the dynamics of measles transmission is important.significance.The infectious disease dynamic model can simulate the transmission dynamics of infectious diseases,and the transmission rate is an important parameter in the transmission characteristics of infectious diseases.Subtle changes in the transmission rate will cause large fluctuations in the number of infectious diseases.Understanding the transmission rate seasonality Formulating immunization strategies has important reference value.This thesis aims to analyze the incidence and risk of measles in different age groups in China,analyzes the seasonality of measles infection rate,and discusses how periodic contact between children and the general population can form the seasonality of measles infection rate in China.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)Infants aged 0-2 are still the main disease group,but in recent years the proportion of adult morbidity has increased significantly,and all age groups have a certain periodicity in different time zones except 2012;2)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 50-65 years;3)The probability of measles being infected after exposure in China(q)is 0.14.Seasonal contact rates that due to both school terms and Spring Festival travel rush will lead to seasonal transmission rate of measles in China,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%.