2017—2019年北京市东城区流感流行病学特征分析

Epidemiological characteristics of influenza in Dongcheng District,Beijing City from 2017 to 2019

目的分析2017—2019年北京市东城区流感流行病学特征。方法对2017—2019年北京市东城区流感样病例的咽拭子样本进行流感病毒核酸检测。选取核酸阳性样本进行细胞分离培养;核酸检测CT<28的样本进行鸡胚分离培养。采用描述性流行病学方法对监测数据进行分析。结果共采集3420份流感样病例咽拭子样本,核酸检测获得阳性样本465份,其中甲型H1N1203份,甲型H3N2133份,乙型BV 13份,乙型BY 116份。2017—2018流感季甲型H1N1、甲型H3N2和乙型BY的检出率较高,分别为5.56%、4.27%和5.79%,2018—2019流感季甲型H1N1检出率较高,为6.34%。不同年龄组间阳性率差异有统计学意义(P<0.001),>59岁年龄组阳性率最高,为17.05%,0~4岁年龄组最低,为6.71%;不同性别样本的阳性率差异无统计学意义(P>0.05)。核酸阳性样本经细胞分离培养获得阳性毒株203株,集中分布于流感病毒核酸阳性样本分布的高峰期。CT<28的核酸阳性样本经鸡胚分离法获得甲型H1N1阳性毒株19株,BY阳性毒株1株。结论北京市东城区冬春季是流感高发季节,60岁以上的老人是流感病毒感染的高发人群,今后应将高发季节对易感人群的保护及健康教育工作作为防控重点,提高预防流感的意识。

Objective To analyze the epidemiological characteristics of influenza in Dongcheng District,Beijing City from 2017 to 2019.Methods Pharyngeal swab samples of influenza-like cases in Dongcheng District,Beijing were collected from 2017 to 2019 and tested for influenza virus nucleic acid,of which the positive ones were cultured in cells while those with measured CT values of less than 28 in chicken embryo.The monitored data were analyzed by descriptive epidemiological method.Results A total of 3420 pharyngeal swab samples,including 465 positive ones,were collected,of which 203 were positive for influenza A H1N1 virus,133 for influenza A H3N2 virus,13 for influenza B BV virus,and 116 for influenza B BY virus.The detection rates of influenza A H1N1,A H3N2 and B BY were relatively high in the influenza season from 2017 to 2018,which were 5.56%,4.27%and 5.79%respectively.However,the detection rate of influenza A H1N1 in the influenza season from 2018 to 2019 was relatively high,which was 6.34%.The positive rate of influenza virus nucleic acid showed significant difference in various age groups(P<0.001),which was the highest in the age group of not less than 60 years(17.05%)and the lowest in that of 0~4 years(6.71%).However,there was no significant difference in the positive rate of influenza virus nucleic acid between two genders(P>0.05).A total of 203 influenza virus strains were isolated from the nucleic acid positive samples,which were mainly distributed in the peak phase when the positive samples appeared.Nineteen influenza A H1N1 virus strains and one influenza B BY strain were isolated by culture in chick embryo from the nucleic acid positive samples with CT values of less than 28.Conclusion The high incidence of influenza in Dongcheng District,Beijing appeared in winter and spring,while the elderly at ages of more than 60 years were the high-risk population.The prevention and control in future should focus on the protection of susceptible population and health education in epidemic season so as to enhance the awareness of influenza prevention.