2005—2021年昆明市流行性感冒发病特征及病原学监测结果分析

Analysis of epidemiological characteristics and etiological surveillance results of influenza in Kunming City From 2005 to 2021

目的分析昆明市2005—2021年流感监测结果及流行特征,为昆明市的流感防控策略的制定和调整提供科学依据。方法对2005—2021年昆明市的流感发病及流感毒株监测情况进行流行病学分析,不同人群的毒株构成差异用χ^(2)检验进行分析,以P<0.05为差异具有统计学意义。结果2005—2019年昆明市的流感发病呈波动上升趋势,2019年流感发病数及发病率均为历年最高,2020年开始流感发病呈下降趋势(χ^(2)趋势=20132.699,P<0.001)。发病的男女性别比为1.1∶1,发病人群以5岁以下婴幼儿为主。2005—2021年昆明市流感监测病例共检出阳性标本1520份,检出毒株中H3(30.7%)和新甲H1N1(28.5%)所占的比例较高;不同性别之间的毒株构成差异无统计学意义(χ^(2)=8.363,P=0.079);不同年龄组的毒株构成差异有统计学意义(χ^(2)=122.135,P<0.001),其中0~19岁人群、60岁以上人群感染的毒株以季H3为主,20~59岁人群感染的毒株以新甲HINI为主;各年流感毒株构成有统计学差异(χ^(2)=1902.834,P<0.001),其中季H3毒株在各年的构成均较高,季H1毒株流行于2009年以前;新甲H1N1毒株在2011年后占比均较高,B型Victoria系(BV)和B型Yamagata系(BY)毒株每隔3~4年交替流行。结论昆明市流感发病及毒株分布都有年龄差异,应根据不同年龄段流感发病特征,采取针对性防控措施。

Objective To analyze the surveillance results and epidemiological characteristics of influenza in Kunming City from 2005 to 2021,and to provide scientific basis for the formulation and adjustment of influenza prevention and control strategy in Kunming City.Methods Epidemiological analysis of influenza incidence and influenza strain surveillance in Kunming City from 2005 to 2021 was carried out.The difference of strain composition in different populations was tested by Chi-square test,and P<0.05 was considered as statistically significant.Results There was a fluctuating 66 upward trend of the influenza morbidity in Kunming City from 2005 to 2019.The morbidity and the number of influenza patients reached to the top in 2019 and began to decline in 2020(χ^(2) tren=20132.699,P<0.001).The male to female sex ratio was 1.1∶1.Meanwhile,the majority of the patients were children under 5 years old.From 2005 to 2021,a total of 1520 positive influenza samples were detected in Kunming City,among which,H3(30.7%)and new H1N1(28.5%)accounted for a high proportion.The difference of strain composition between different genders showed no statistically significant(χ^(2)=8.363,P=0.079).However,the differences of strain composition among different age groups were statistically significant(χ^(2)=122.135,P<0.001).The main strain of infection among 0-19 years old and over 60 years old age groups was seasonal H3,and the main strain among 20-59 years old age group was new HINI.There were statistical differences in the composition of influenza strains in each year(χ^(2)=1902.834,P<0.001).The composition of seasonal H3 strain was higher in each year,and seasonal H1 strain was prevalent before 2009.The proportion of new H1N1 strain was high after 2011,and B type Victoria(BV)and B type Yamagata(BY)strains alternated every 3-4 years.Conclusions There were age differences in the incidence and distribution of influenza strains in Kunming City.We should take targeted prevention and control measures based on the characteristics of influenza in different age groups.