Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Front Public Health. 2023 Jun 22;11:1189969. doi: 10.3389/fpubh.2023.1189969. eCollection 2023.
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a global threat since 2020. The emergence of the Omicron variant in 2021, which replaced Delta as the dominant variant of concern, has had a significant adverse impact on the global economy and public health. During this period, Zhejiang Province implemented dynamic zeroing and focused on preventing imported cases. This study aimed to gain clear insight into the characteristics of imported COVID-19 cases in Zhejiang Province.
We conducted a systematic molecular epidemiological analysis of 146 imported cases between July 2021 and November 2022 in Zhejiang Province. Virus samples with cycle threshold (Ct) value less than 32 were performed next generation sequencing. Basing the whole genome sequence obtained after quality control and assembly of reads, the whole genome variation map and phylogenetic tree were constructed and further analyzed.
Our study identified critical months and populations for surveillance, profiled the variation of various lineages, determined the evolutionary relationships among various lineages of SARS-CoV-2, and compared the results in Zhejiang with those obtained worldwide during this period.
The continuous molecular epidemiological surveillance of imported cases of COVID-19 in Zhejiang Province during 2021 to 2022 is consistent with the global epidemic trend.
自 2020 年以来，由严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）引起的 2019 年冠状病毒病（COVID-19）大流行一直是全球威胁。2021 年奥密克戎变异株的出现取代了德尔塔成为主要关注的变异株，对全球经济和公共卫生产生了重大不利影响。在此期间，浙江省实施动态清零，重点防范输入性病例。本研究旨在深入了解浙江省输入性 COVID-19 病例的特征。
我们对 2021 年 7 月至 2022 年 11 月期间浙江省 146 例输入性病例进行了系统的分子流行病学分析。对循环阈值（Ct）值小于 32 的病毒样本进行下一代测序。在对读取进行质量控制和组装后，基于获得的全基因组序列构建全基因组变异图谱和系统发育树，并进一步进行分析。
我们的研究确定了需要监测的关键月份和人群，分析了各种谱系的变异情况，确定了 SARS-CoV-2 各谱系之间的进化关系，并将浙江省的结果与同期全球的结果进行了比较。
2021 年至 2022 年期间，浙江省对输入性 COVID-19 病例的持续分子流行病学监测与全球流行趋势一致。
