烟台市一起新型冠状病毒肺炎聚集疫情调查分析

目的 了解一起新型冠状病毒肺炎(简称新冠肺炎)聚集性疫情的传播特征和传播链,做好密切接触者的追踪和判定,为开展疫情防控提供参考。 方法 按照《新型冠状病毒肺炎防控方案(第四版)》开展现场流行病学调查,同时采集呼吸道标本开展新冠病毒核酸检测。 结果 该起聚集性疫情涉及病例12例,其中无症状感染者4例和确诊病例8例。确诊病例潜伏期一般为3~6 d,中位数5 d;发病至就诊的时间间隔为1~4 d,中位数为2 d。确诊病例8人中,普通型6人,重型2人。该起疫情出现了四代病例,其中一代病例1人、二代病例5人、三代病例2人、四代病例4人。 结论 此次聚集性疫情潜伏期和代际关系明确,确诊病例潜伏期和无症状感染者具有传染性。

Investigation and analysis on a cluster epidemic of COVID-19 in Yantai City

Objective To investigate the transmission characteristics and transmission chains of a cluster epidemic caused byCOVID-19,to trace and test close contacts of the identified cases,and to provide evidence for prevention and control of the epidemic.Methods Field epidemiological investigation was conducted according to COVID-19 Prevention and Control Scheme(4 th Edition),and respiratory specimens were simultaneously collected for severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)nucleic acid detection.Results Twelve cases with positive results for nucleic acid test were involved in the cluster infection,including 4 asymptomatic carriers and 8 confirmed cases.The incubation period of the confirmed cases was generally 3-6 days,with the median of 5 days.The interval between onset of symptoms and visiting a doctor ranged from 1 to 4 days,with the median of 2 days.Among the 8 confirmed cases,6 were classified as ordinary cases and the other 2 as severe cases.4 generations of infections were detected in the cluster epidemic,with 1 case in the first generation,5 cases in the second generation,2 cases in the third generation and 4 cases in the fourth generation.Conclusions There were clearly identified incubation period and intergeneration relationships in this cluster infection.Risk of interpersonal transmission was present during incubation period of the confirmed cases and also among the asymptomatic carriers.