瑞丽市2021年7—11月COVID-19境外输入病例分子流行病学分析

Molecular epidemiological analysis of COVID-19 imported cases in Ruili from July to November,2021

目的分析瑞丽市境外陆路输入COVID-19病例的流行特征和基因组特征,为云南省边境疫情防控工作提供参考依据。方法收集2021年7月至11月瑞丽市境外陆路输入SARS-CoV-2感染者相关信息,对流行病学特征进行统计分析;筛选40例阳性样本使用Illumina公司二代测序平台进行高通量测序,分析基因分型情况及变异特征。结果研究期间瑞丽市累计报告SARS-CoV-2感染者796例,年龄范围1~85岁,年龄[M(IQR)]为28.5(10)岁;男女性别比4.61∶1;职业以商业服务49.75%(396/796)为主;轻型、普通型占比95.60%。获得的34例测序结果按照Nextstrain分型法可分为3个型,24例属于21A(Delta)分支,9例属于21I(Delta)分支,1例属于20I(Alpha,V1)分支。结论本研究中的病例病毒基因分型主要分为三大支系且互相之间有一定差异,其中大部分为Delta株。应继续落实好边境管控措施,持续对境外输入病例进行病毒变异监测,以评估变异株对云南省疫情防控现状的威胁。

Objective To analyze the epidemiological and genomic characteristics of COVID-19 cases imported by land in Ruili,and to provide reference for border epidemic prevention and control in Yunnan Province.Methods We collected information about SARS-CoV-2 infected individuals from overseas land in Ruili,Yunnan from July to November,2021.The epidemiological characteristics were statistically analyzed.The second-generation sequencing platform of Illumina was used to conduct high-throughput sequencing on the selected 40 positive samples and to analyze their genotyping and variation characteristics.Results During the study period,Ruili City reported 796 COVID-19 cases from abroad.The median age of COVID-19 cases was 28.5 years(Interquantile range 10;range 1-85).The gender ratio between men and women was 4.61∶1;Most of these infected individuals engaged in business services,accounting for 49.75%(396/796);95.60%of COVID-19 cases were mild and moderate cases.The sequencing results of 34 cases can be divided into three clades according to Nextstrain typing method,including 24 cases belong to 21A(Delta)clade,9 cases belong to 21I(Delta)clade and 1 case belongs to 20I(Alpha V1)clade.Conclusions The virus genotypes of the cases in this study were mainly divided into three branches and there were some differences among them,most of which were Delta mutants.We should continue to implement border control measures and continue to monitor the virus mutation of imported cases,so as to evaluate the threat of the mutant strain to the current situation of epidemic prevention and control in Yunnan Province.