2009—2014年北京市中心城区流行性感冒的流行特征分析

Epidemiological characteristics of influenza in downtown areas of Beijing City from 2009-2014

目的了解北京市中心城区流行性感冒（简称流感）的流行动态,为及时预警预测流感活动强度和流感防制提供科学依据。方法应用北京市医院传染病监测预警系统和国家流感监测网络,收集2009—2014年中心城区2所三级甲等哨点医院流感样病例（ILI）流行病学和核酸检测资料,比较5个年度不同年龄组间ILI报告数、核酸检测阳性率有无差异,并分析ILI与核酸检测阳性率的相关性。结果 2009年6月—2014年5月共报告ILI 128 482例,其就诊百分比平均为1.74%。5个年度ILI%分别为2.38%、2.02%、1.28%、1.57%、0.99%。期间共检测ILI标本9 664件,检出阳性标本2 231件,阳性率为23.09%。5个年度流感病毒检测阳性率分别为39.70%、23.38%、21.90%、12.99%、17.33%。不同年龄组间阳性率差异有统计学意义（χ2=103.60,P〈0.05）;不同季节间阳性率差异有统计学意义（χ2=938.10,P〈0.05）。ILI数与同期ILI就诊比例呈正相关关系（r=0.865,P〈0.05）,流感阳性率与ILI数呈正相关关系（r=0.642,P〈0.05）,流感阳性率与ILI就诊比例呈正相关关系（r=0.613,P〈0.05）。结论流感活动存在明显的秋冬季高峰。ILI发病年龄以60岁~年龄组为主,但2009—2011年度5~14岁年龄组发病率也较高。ILI流行特征与流感病毒活动趋势基本一致。通过提高ILI报告质量、标本采集质量及监测方案的适时调整,可以获得更加科学有效的流感监测工作效果。

[Objective]To understand the epidemic trend of influenza in downtown areas of Beijing,so as to provide scientific evidence for early warning of influenza activity and the control and prevention of influenza.[Methods]The early warning system for infectious disease in medical institutions and the National Influenza Surveillance Network was used,the data of Influenza-like illness（ILI） surveillance and nucleic acid detection from 2009-2014 in 2 sentinel hospitals in downtown areas of Beijing were collected. The ILI number and the positive rate of nucleic acid in different age groups were compared between 5 years. And the correlation of ILI and the positive rate was analyzed. [Results]A total of 128 482 ILI cases were reported from June 2009-May2014,the average proportion of ILI cases in outpatients was 1.74%. The annual proportion of ILI cases was 2.38%,2.02%,1.28%,1.57% and 0.99%,respectively. Totally 9 664 samples from ILI cases were detected,of which 2 231 were positive,and the positive rate was 23.09%. The annual positive rate was 39.70%,23.38%,21.90%,12.99% and 17.33%,respectively in 5years. The differences of the positive rates had a statistical significance among different age groups（χ2=103.60,P 〈0.05） and different seasons（χ2=938.10,P 〈0.05）. The ILI number and the rate of ILI had a positive correlation（r =0.865,P 〈0.05）. The positive rate of influenza and the influenza-like illness number had a positive correlation（r=0.642,P〈0.05）. The positive rate of influenza and the outpatient rate of ILI had a positive correlation（r=0.613,P〈0.05）.[Conclusion]The influenza activity appears obvious peak in winter and autumn. A great number of ILI cases are old people aged over 60 years,and during 2009-2011,children aged 5-14 years had a high incidence of ILI. The characteristics of ILI incidence are similar to the activity of influenza virus. More scientific and effective influenza surveillance can be achieved by improving the quality of ILI reporting and specimen collection and adjustment the monitoring program.