2016-2019年中山市流行性感冒季节性流行特征分析

目的 分析2016-2019年中山市流感季节性流行特征，为加强流感防控提供依据。方法 收集2016-2019年中山市流感监测数据和报告病例数，比较流感样病例就诊指数（ILI%）、报告病例数、病毒阳性率、病毒分型以及暴发疫情等特点。 结果 2016-2019年中山市平均ILI%为4.92%（717525/14593406）。2016年ILI%高峰出现在春季，2017年在夏季，2018年在冬季，2019年出现冬季流行高峰和春夏季流行小高峰，流行持续30周。累计报告病例数65535例，6~14岁年龄组占比最大（32.88%），以2019年报告病例数最多。4个年度ILI监测样本的病毒总体阳性率为19.73%（559/7902），其中A（H1N1）占6.59%（521/7902），A（H3N2）占6.81%（538/7902），B亚型占6.30%（498/7902），A（H1N1）和A（H3N2）混合感染占0.03%（2/7902）。2016年流行高峰期的优势毒株为A(H1N1)和B亚型，后转以A（H3N2）为主；2017年流行毒株是A（H3N2）；2018年以B亚型和A(H1N1)为主 ；2019年年初冬季阳性标本以A(H1N1)为主，春季开始逐渐进入A（H1N1）、A（H3N2）和B亚型共同流行模式，夏季以B亚型为主，年底冬季以A（H3N2）为主要流行型别。6~14岁年龄组流感病毒阳性率最高（34.09%,317/930），以A（H3N2）为主（13.44%，125/930）。4年累计报告流感暴发疫情42起，多发生在冬春季，小学是主要暴发场所（66.67%，28/42）。ILI%与报告病例数、流感病毒阳性率均呈正相关（r分别为0.673和0.745，P均<0.001）。结论 2016-2019年中山市出现了由不同型别流感病毒引起的流感季节性流行，其中2019年出现了多个型别流感病毒共同轮换、流行强度大、持续时间长的流行。加强监测和推广接种流感疫苗可有效防控多样化的流感季节性流行。

Epidemiological characteristics analysis of influenza in Zhongshan,2016-2019

To investigate the epidemiologic characteristics of influenza in Zhongshan City from 2016 to 2019 inorder to enhance the influenza prevention and control.Methods Data on weekly influenza surveillance and cases reportedfrom 2016 to 2019 were collected in Zhongshan City.Influenza－like illness percentage(ILI%)，influenza cases，influenzavirus positive rate，virus type and influenza outbreaks were analyzed and compared.Ｒesults The average level of ILI%from2016 to 2019 was 4.92%(717525/14593406).The peak time of ILI%was in spring in 2016，summer in 2017，winter in2018，and there was a peak in winter and a small peak in spring and summer in 2019 which lasted for 30 weeks.Thecumulative number of reported cases was 65535，and the age group of 6－14 years accounted for the largest proportion(32.88%)，with the largest number of reported cases in 2019.The overall influenza virus positive rate of ILI outpatient was19.73%(559/7902)，in which A(H1N1)accounted for 6.59%(521/7902)，A(H3N2)accounted for 6.81%(538/7902)，B subtype accounted for 6.30%(498/7902)，A(H1N1)and A(H3N2)mixed infection accounted for 0.03%(2/7902).The prevalent subtypes in the epidemic peak in 2016 were A(H1N1)and B subtype，followed by A(H3N2).It wasA(H3N2)in 2017，and in 2018 it was the B subtypes and A(H1N1).In 2019 A(H1N1)was the mainly positive specimenin winter，then gradually entered the pattern of A(H1N1)，A(H3N2)and B subtype in spring，in summer B subtype was thedominant，and at the end of the year A(H3N2)turned to be the main type.The positive rate of influenza virus in 6－14 yearsold group was the highest(34.09%，317/930)，and most of the virus were A(H3N2)which accounted for 13.44%(125/930).42 influenza outbreaks occurred，mostly in winter and spring，and primary schools were the main outbreak sites(66.67%，28/42).ILI%was positively correlated with the number of reported cases and the positive rate of influenza virus(r=0.673 and r=0.745，P＜0.001).Conclusion From 2016 to 2019，there were seasonal epidemics of influenza caused bydifferent types of influenza viruses in Zhongshan City.In 2019，several types of influenza viruses rotated together with highepidemic intensity and long duration.Strengthening the surveillance and promoting the influenza vaccine can effectively preventand control the diversified seasonal influenza epidemics.Keywords:Influenza;Seasonal;Surveillance;Epidemiological characteristics