2022年浙江省春季新型冠状病毒感染本土聚集性疫情流行病学特征分析

Epidemiological characteristics of local COVID-19 epidemic in Zhejiang in spring of 2022

目的 分析自2022年3月以来浙江省本土新型冠状病毒感染(新冠)聚集性疫情流行病学特征。方法 收集2022年3月3日至5月8日浙江省本土新冠聚集性疫情的流行病学调查资料,采用描述性流行病学方法进行分析。结果 262起疫情波及11个市的71个县(市、区),累计报告确诊病例668例,无症状感染者866例。局部空间自相关分析显示,嘉善县、平湖市、海宁市、临平区、余杭区、拱墅区、上城区和婺城区存在热点聚集性。本次疫情由上海市输入并导致关联疫情占72.90%;50例以上规模疫情持续时间为7~15 d,10 d左右控制动态基本再生数(R_(t))<1。结论 本轮疫情主要发生在嘉兴市和杭州市,大部分是外省输入病例引起的关联疫情;疫情R_(t)控制在1以下的时间越早,规模越小,疫情持续时间越短。

Objective To analyze the epidemiological characteristics of local COVID-19 epidemic in Zhejiang province in spring of 2022.MethodsThe epidemiological data of local COVID-19 epidemic in Zhejiang from March 3 to May 8,2022 were collected,and descriptive epidemiological method were used for analysis.Results A total of 262 clusters of COVID-19 cases were reported in this epidemic in 71 counties(districts)in 11l prefectures(municipality)in Zhejiang,a total of 668 symptomatic cases and 866 asymptomatic cases were diagnosed.Local spatial autocorrelation analysis showed the clustering hot spots in Jiashan county,Pinghu and Haining cities,Linping,Yuhang,Gongshu,Shangcheng and Wucheng districts.Up to 72.90% of COVID-19 case clusters were caused by the imported cases from Shanghai;the duration of the virus spread in clusters with more than 50 cases ranged from 7 to 15 d,and the dynamic basic reproduction number(R_(t))was kept below 1 for about 10 d.ConclusionsThis round of epidemic mainly occurred in Jiaxing and Hangzhou due to local SARS-CoV-2 transmission caused by imported cases from other provinces;the earlier the R_(t),declined below 1,the smaller the epidemic scale and the short the epidemic duration.