基于移动流行区间法的浙江省宁波市冬春季流行性感冒流行强度研究

Application of moving epidemic method to study influenza epidemic intensity in winter and spring in Ningbo

目的利用移动流行区间法(MEM)研究浙江省宁波市流行性感冒(流感)流行季节流行强度,建立流感监测预警机制,为采取防控措施提供依据。方法利用宁波市2013-2018年冬春流感流行季(第40周至次年第20周)病毒检出阳性率为基线数据,建立MEM模型,分析宁波市2018-2019年冬春流感流行季的流行强度。结果 2018-2019年宁波市冬春季流感流行期开始阈值为22.68%,流行结束阈值为23.32%。2018年第40周到2019年第1周为流行前期;在2019年第2周流感突破流行开始阈值进入低流行阶段;从第3周开始达到中等流行强度;第8-9周,宁波市流感进入高流行阶段;第10-14周流行降低为中流行强度;第14-18周再降为低流行强度;第19周以后处于流行后期。本次建立的MEM模型灵敏度为80.04%,特异度为87.18%,拟合优度较好。结论利用MEM建立流感预警模型,可计算流感流行开始时间和流行强度,并能直接评价模型优劣,为流感流行的早期识别和预警防控工作提供科学依据。

Objective To use moving epidemic method(MEM)to study the epidemic intensity of seasonal influenza epidemic in Ningbo,establish influenza surveillance and early warning mechanism and provide evidence for the prevention and control of influenza.Methods The positive rates of virus detection in winter and spring influenza season in Ningbo from 2013 to 2018 40th week to the 20th week next year)were used,the MEM model was established to analyze the epidemic intensity of the seasonal influenza epidemic in Ningbo from 2018 to 2019.Results In the period of 2018–2019,the threshold of the initial influenza epidemic period in Ningbo was 22.68%,and the threshold of the late epidemic period was 23.32%.The initial epidemic period was from the 40th week of 2018 to the 1st week of 2019.In the 2nd week of 2019,the influenza incidence broke through the initial threshold and the epidemic intensity was low,and a medium epidemic intensity was recorded from the3rd week.From the 8th week to the 9th week,the influenza epidemic intensity was high.The epidemic intensity gradually decreased to medium level from the 10th week to the 14th week and reached a low epidemic level from the 14th week to the 18th week.After the 19th week,it was the late epidemic period.The sensitivity of the MEM model was 80.04%,the specificity of the MEM model was 87.18%.The goodness of the model was good.Conclusion The start time and intensity of influenza epidemic can be calculated by using the influenza early warning model established with MEM,and the model can be directly evaluated.This method provides a scientific basis for the early identification and early warning of influenza epidemic.