移动流行区间法在评估江苏省流感流行强度中的应用研究

Study on the Assessment of Epidemic Intensity of Influenza by the Moving Epidemic Method in Jiangsu Province

目的探索移动流行区间法(moving epidemic method,MEM)在评估江苏省流感流行强度中的应用,为流感分级预警提供科学依据。方法基于2010-2017年每年第39周至次年第21周江苏省流感病毒的核酸阳性率数据进行建模,采用灵敏度、特异度、约登指数作为评价指标选择最优模型,并以此评估2017年第39周至2018年第21周江苏省流感的流行强度。结果选择2010-2017年每年第39周至次年第21周(经交叉验证,剔除2012-2013和2016-2017两个流行季后,最终实际纳入5个冬春流行季)的江苏省流感病毒核酸阳性率为评估基线,参数δ取值为2.2时,建立的MEM模型表现最优,合计灵敏度、特异度及约登指数分别为0.9465、0.8632及0.8097。2017年第50周我省进入流感流行期,于2018年第13周结束流行,期间流行持续达15周之久,其中高强度流行3周、中强度流行7周、低强度流行5周。结论MEM可作为江苏省识别流感流行和评估流行强度的方法。

Objective To evaluate the epidemic intensity of influenza by the moving epidemic method(MEM)in Jiangsu province,and to provide evidences for the classification of early warning of influenza.Methods Weekly laboratory confirmed influenza rates between the 39th week and the 21st week of the following year were modeled for the 2010/2011-2016/2017 seasons using MEM.Then the performance of the model was evaluated by sensitivity,specificity and Youden index.Finally,the epidemic intensity of influenza from the 39th week in 2017 to the 21stweek in 2018 was assessed.Results Weekly data from 2010/2011 to 2015/2016(not including 2012/2013)were taken to establish the optimal model.The optimal parameterδwas 2.2.The overall sensitivity,specificity and Youden index of the optimal model was 0.9465,0.8632 and 0.8097,respectively.The influenza epidemic which lasted for 15weeks was beginning from the 50th week,2017 and ended in the 13th week,2018.Among them,high intensity level,medium intensity level and low intensity level continued for 3,7 and 5 weeks,respectively.Conclusion The MEM may serve as a practical method to detect the influenza epidemic and estimate the epidemic intensity in Jiangsu province.