临沂市学校流感暴发疫情病毒检出特征分析

Detection characteristics of the virus during school influenza outbreaks in Linyi City

目的分析学校流感暴发疫情中流感病毒的检出特征,为学校流感暴发疫情处置提供策略依据。方法对2021—2022年度临沂市报告的52起中小学校流感暴发疫情进行分析,共采集咽拭子样本1702份,处置疫情时将采样对象按照不同症状分为3种类型[A组:流感样病例(ILI)组;B组:轻症组;C组:密接组],对采集的样本采用实时荧光定量方法检测流感病毒核酸。采用χ^(2)检验对流感暴发疫情中病毒检出率进行分析。结果共检出流感病毒核酸阳性1071份(62.93%),其中A组采样726份,检出610份(84.02%);B组采样634份,检出331份(52.21%);C组采样342份,检出130份(38.01%),差异有统计学意义(χ^(2)=260.71,P<0.01)。按照性别分析,A组男性流感病毒核酸阳性检出率80.83%,女性91.36%;B组男性53.31%,女性50.87%;C组男性30.72%,女性43.92%,其中A组和C组的性别间差异均有统计学意义(χ^(2)值分别为12.67,6.25,P值均<0.05)。按发病天数,发病0~6 d的流感病毒核酸阳性检出率分别为56.30%,74.49%,89.35%,86.23%,69.67%,62.75%,34.33%,差异有统计学意义(χ^(2)=128.27,P<0.01)。结论轻症病例和密切接触者人群可能是造成学校流感暴发疫情中班级内病例长时间持续新发的重要原因,且流感症状的演进与其传染风险有关系。

Objective To analyze the characteristics of influenza virus detection in an influenza outbreak in schools,so as to provide a strategic basis for the treatment of influenza outbreaks in schools.Methods A total of 1702 samples were collected from 52 school influenza outbreaks reported in Linyi City in 2021-2022.The samples were divided into 3 types according to different symptoms during the management of the epidemic[group A:influenza-like illness(ILI)group;group B:mild illness group;group C:close contacts group].Rt-PCR was used to detect influenza virus nucleic acid in the collected samples.The detection rate of influenza virus in the outbreaks was analyzed byχ^(2) test.Results In total,1071 samples(62.93%)tested positive for influenza virus nucleic acid.Among them,610 out of 726 samples(84.02%)were detected in group A,while 331 out of 634 samples(52.21%)were detected in group B.In group C,130 out of 342 samples(38.01%)tested positive.The differences were statistically significant(χ^(2)=260.71,P<0.01).In group A,males had a detection rate of 80.83%for influenza virus nucleic acid,compared to 91.36%for females.For group B,the rates were 53.31%for males and 50.87%for females.In group C,males had a rate of 30.72%,while females had a rate of 43.92%.Statistical significance for gender differences was observed only in groups A and C(χ^(2)=12.67,6.25,P<0.05).According to the days of onset,the detection rates of influenza virus nucleic acid among patients with onset 0-6 days were 56.30%,74.49%,89.35%,86.23%,69.67%,62.75%,34.33%,respectively,and the difference was statistically significant(χ^(2)=128.27,P<0.01).Conclusions Mild cases and close contacts are likely key factors contributing to the prolonged emergence of new cases within classrooms during school influenza outbreaks.The progression of influenza symptoms is related to the risk of transmission.