浙江省境外输入新型冠状病毒肺炎病例流行特征

Epidemiological characteristics of overseas imported COVID-19 cases in Zhejiang Province

目的分析浙江省境外输入新型冠状病毒肺炎(COVID-19)病例的流行病学特征,为境外输入COVID-19疫情防控提供参考。方法通过中国疾病预防控制信息系统收集2020年1月1日—2022年5月31日浙江省境外输入COVID-19病例资料,采用描述性流行病学方法分析病例的时间、地区和人群分布,分析入境至首次新型冠状病毒(新冠病毒)核酸检测阳性时间和新冠病毒疫苗接种情况。结果2020年1月1日—2022年5月31日浙江省共报告境外输入COVID-19病例1535例,其中确诊病例596例,无症状感染者939例。病例来自102个国家和地区。除2020年5月外,各月份均有境外输入病例报告,2021年12月—2022年5月月均报告125例。11个市均有境外输入病例报告,杭州市和嘉兴市报告数较多,分别为978例和177例;县区覆盖率为76.09%。病例以中国籍为主,占88.79%;年龄20~<40岁占59.09%;职业以学生、工人和商业服务人员居多,分别占21.82%、17.20%和17.00%。入境至首次新冠病毒核酸检测阳性时间间隔M(Q_(R))为3.98(7.06)d,2021年12月1日—2022年5月31日期间为3.23(4.97)d,较2020年1月1日—2021年11月30日期间明显缩短(P<0.001)。未接种新冠病毒疫苗病例的临床分型普通型及以上占15.69%,高于完成加强接种的病例(7.77%;χ^(2)=5.345,P=0.021),与完成全程接种病例比较差异无统计学意义(12.65%;χ^(2)=0.971,P=0.324)。结论2020年1月1日—2022年5月31日,浙江省境外输入COVID-19病例以中国籍学生、工人和商业服务人员为主;2021年12月1日后入境病例发现时间缩短,加强接种新冠病毒疫苗有助于降低临床症状的严重程度。浙江省境外输入COVID-19风险将长期存在,需持续落实好入境人员防控管理。

Objective To analyze the epidemiological characteristics of overseas imported cases with coronavirus disease 2019(COVID-19)in Zhejiang Province,so as to provide insights into containment of overseas imported COVID-19.Methods The pertaining to overseas imported COVID-19 cases in Zhejiang Province during the period between Janu⁃ary 1,2020 and May 31,2022 were captured from the Chinese Disease Prevention and Control Information System.The temporal,spatial and population distributions,the duration from entry to the first time of positive severe acute respi⁃ratory syndrome coronavirus 2(SARS-CoV-2)nucleic acid test,and COVID-19 vaccination of overseas imported COVID-19 cases were analyzed using a descriptive epidemiological method.Results A total of 1535 overseas import⁃ed COVID-19 cases were reported in Zhejiang Province during the period between January 1,2020 and May 31,2022,including 596 confirmed cases and 939 asymptomatic infections,and all reported cases were imported from 102 coun⁃tries and territories.Overseas imported COVID-19 cases were reported in each month during the period between March 2020 and May 2022 except May 2020,and the mean monthly number of reported overseas imported COVID-19 cases was 125 during the period between December 2021 and May 2022. Overseas imported COVID-19 cases were reported across 11 cities of Zhejiang Province, with the largest numbers reported in Hangzhou (978 cases) and Jiaxing cities (177 cases), and imported cases were reported in 76.09% of counties (districts) in Zhejiang Province. The overseas im⁃ ported COVID-19 cases were predominantly identified among individuals with Chinese nationality (88.79%), at ages of 20 to 39 years (59.09%), and students (21.82%), workers (17.20%) and business servants (17.00%) were predominant oc⁃ cupations among the overseas imported COVID-19 cases. The median duration from entry to the first time of positive SARS-CoV-2 nucleic acid test was 3.98 (7.06) d during the period between January 1, 2020 and May 31, 2022, and was 3.23 (4.97) d during the period between December 1, 2021 and May 31, 2022, which was significantly shorter than that during the period between January 1, 2020 and November 30, 2021 (P<0.001). The proportion of normal and more severe types of COVID-19 was 15.69% among cases without COVID-19 vaccination, which was significantly higher than that (7.77%) among those receiving booster vaccination (χ^(2)=5.345, P=0.021), but was not significantly different from that (12.65%) among those receiving full-dose vaccination (χ^(2)=0.971, P=0.324). Conclusions Students with Chinese nationality, workers and business servants were predominant among overseas imported COVID-19 cases in Zhejiang Province until May 31, 2022. The duration from entry after December 1, 2021 to identification of overseas imported COVID-19 cases shortened, and booster COVID-19 vaccination facilitated the alleviation of severity of clinical symp⁃ toms. There is a long-term risk of overseas importation of COVID-19 in Zhejiang Province, and the containment of im⁃ ported COVID-19 requires to be sustainably implemented among entry personnel.