2010-2021年上海市闵行区流感样病例及病原学特征

Influenza-like illnesses and their etiological characteristics in Minhang District of Shanghai during 2010 to 2021

目的了解2010-2021年上海市闵行区流感样病例(ILI)的流行病学特征及流感病毒的病原学动态变化趋势。方法利用上海市闵行区2010年第1周—2021年第52周共12个监测年度间的流感监测哨点医院和流感网络实验室的监测数据进行统计分析。结果2010—2021年上海市闵行区国家级流感监测哨点医院共报告122903例ILI,年平均流感样病例百分比(ILI%)为0.94%,总体呈现上升趋势(P<0.001)。ILI中,0~4岁、5~14岁、15~24岁、25~59岁、≥60岁年龄组病例分别占4.35%、13.30%、14.30%、54.32%、13.73%。ILI%呈现明显的周期性,12月—次年2月为冬季高峰,7-9月为夏季高峰,2013年初的冬季高峰有所推延,2021年未出现明显就诊高峰。2010-2021年闵行区共检测ILI标本11625份,流感病毒阳性率为20.92%(2432/11625),甲型流感病毒阳性率为12.83%(1492/11625),乙型流感病毒阳性率为8.09%(940/11625),甲型流感的流行强度高于乙型流感。2010-2021年各型流感病毒的总体阳性率:甲型H3N2(1051,9.04%)>甲型H1N1(441,3.79%)>乙型Victoria系(313,2.69%)>乙型Yamagata系(255,2.19%),2010-2019年间上海市闵行区甲型流感与乙型流感交替流行,且每种流行株大概持续半年时间被新流行株所替代,2020、2021年没有明显的规律性。2010—2019年报告的ILI数量和流感病毒阳性率的变化趋势基本一致,2020、2021年的变化趋势有明显差别。结论上海市闵行区流感呈现季节性流行,且各亚型流感病毒交替或混合成优势毒株流行,发病集中在冬季和夏季。COVID-19疫情防控期间流感流行强度下降,但伴随疫情防控逐渐常态化,流感流行呈明显上升趋势,故应继续加强流感的防控与监测,并及时对病毒变异情况进行分析。

Objective To investigate the epidemiological characteristics of influenza-like illnesses(ILI)and the etiological characteristics of influenza viruses in Minhang District of Shanghai from 2010 to 2021.Methods The surveillance data collected by influenza surveillance sentinel hospitals and the influenza laboratory network from the first week of 2010 to the 52nd week of 2021 were used for a statistical analysis.Results A total of 122903 cases with ILI were reported by the national influenza surveillance sentinel hospitals in Minhang during 2010 to 2021,and the average percentage of ILI cases was 0.94%,showing an increasing trend(P<0.001).Among them,those aged 0-4,5-14,15-24,25-59 and≥60 years accounted for 4.35%,13.30%,14.30%,54.32%and 13.73%,respectively.The percentage of ILI showed obvious periodicity.The seasonal incidence of ILI peaked from December to February and from July to September.But the winter peak at the beginning of 2013 was postponed.There was no significant peak in 2021.A total of 11625 samples were tested from 2010 to 2021,in which the detection rate of influenza viruses was 20.92%(2432/11625).The positive rate was 12.83%(1492/11625)for influenza A viruses and 8.09%(940/11625)for influenza B viruses,indicating that the epidemic intensity caused by influenza A viruses was greater than that caused by influenza B viruses.The overall positive rates for influenza A/H3N2 virus,influenza A/H1N1 virus,influenza B/Victoria lineage and influenza B/Yamagata lineage were 9.04%(1051/11625),3.79%(441/11625),2.69%(313/11625)and 2.19%(255/11625)during 2010 to 2021.The predominant circulating strains altered between influenza A and influenza B viruses in Minhang District of Shanghai during 2010 to 2019.It generally took six months for an epidemic strain to be replaced by a new one.No obvious regularity was observed in 2020 or 2021.The tendency of the incidence of ILI reported from 2010 to 2019 was basically the same as that of the positive rate of influenza viruses,while there were significant differences in 2020 and 2021.Conclusions Influenza viruses circulated seasonally in Minhang District of Shanghai with alternating prevalent viral subtypes and the infections mostly occurred in the winter and summer seasons.During the epidemic of COVID-19,the intensity of influenza was decreased,but with the normalization of prevention and control measures,the influenza epidemic showed an obvious upward trend.Therefore,it was important to strengthen the prevention and monitoring of influenza and analyze the virus variations in time.