我国输入性新型冠状病毒感染者核酸检测阳性的时间分布特征

目的分析全国报告的输入性新型冠状病毒(新冠病毒)感染者核酸首次阳性的时间分布特征, 为进一步完善入境人员的新型冠状病毒肺炎疫情防控措施提供参考依据。方法收集2020年7月24日至2021年7月23日各省报告的输入性新冠病毒感染者资料, 对入境后核酸首次阳性的时间分布特征进行分析。结果 2020年7月24日至2021年7月23日全国28个省份共报告7 199例输入性新冠病毒感染者, 从入境至核酸首次阳性的时间间隔M(Q1, Q3)为1(0, 5)d。在输入性新冠病毒感染者中, 入境14 d内和14 d后核酸首次阳性者分别占95.15%(6 850/7 199)和4.85%(349/7 199), 入境15～21 d内、22～28 d内和28 d后核酸首次阳性者分别占3.65%(263/7 199)、0.88%(63/7 199)和0.32%(23/7 199)。在入境14 d内和14 d后核酸首次阳性者中, 无症状感染者分别占47.24%(3 236/6 850)和63.61%(222/349)。39.54%(138/349)的入境14 d后核酸首次阳性者在入境地解除集中隔离后存在跨省流...

Time distribution of positive nucleic acid detection in imported cases infected with SARS-CoV-2 in China

Objective To analyze the time distribution of the first positive nucleic acid detection in imported cases infected with SARS-CoV-2 reported nationwide in China and provide references for further improvement of the prevention and control of COVID-19 in international travelers.Methods The data of imported cases infected with SARS-CoV-2 reported by provinces from 24 July 2020 and 23 July 2021 were collected for the analysis on the time distribution of the first positive nucleic acid detection after entering China.Results A total of 7199 imported cases infected with SARS-CoV-2 were reported in 28 provinces during 24 July 2020 to 23 July 2021.The median interval(Q1,Q3)from the entry to the first positive nucleic acid detection of SARS-CoV-2 was 1(0,5)day.The imported cases who had the first positive nucleic acid detections within 14 days and 14 days later after the entry accounted for 95.15%(6850/7199)and 4.85%(349/7199)respectively.Among these cases,3.65%(263/7199),0.88%(63/7199)and 0.32%(23/7199)had the first positive nucleic acid detections within 15-21 days,22-28 days and 28 days later after the entry respectively.The proportion of asymptomatic infections were 47.24%(3236/6850)and 63.61%(222/349)among the cases who had the first positive nucleic acid detections within 14 days and 14 days later after the entry respectively.A total of 39.54%(138/349)of cases infected with SARS-CoV-2 with the first positive nucleic acid detections 14 days later after the entry had inter-provincial travel after the discharge of entry point isolation.Conclusions About 5%of the imported cases infected with SARS-CoV-2 were first positive 14 days later after the entry.In order to effectively reduce the risk of domestic COVID-19 secondary outbreaks caused by imported cases,it is suggested to add a nucleic acid test on 8^th-13^th day after the entry.