郴州地区一起无症状感染者引起新型冠状病毒肺炎家庭聚集性疫情

Report of COVID-19 family clustering epidemic caused by asymptomatic infection

目的分析一起无症状感染者引起COVID-19家庭聚集性疫情,为制定COVID-19防控策略提供参考依据。方法2020年1月31日-2月6日,在郴州市某县应用流行病学调查方法,对一起聚集疫情进行现场流行病学调查;采用实时荧光定量聚合酶链式反应(Real-time PCR)对咽拭子标本进行SARS-CoV-2核酸检测;描述性分析病例传播链、病例代际和无症状感染者传染性。结果本起疫情发生在一个家庭,6天内发现4例确诊病例(A、C、D、E)和1例无症状感染者(B),B在武汉疫区感染传播给C,因家庭共同生活,由B、C传播给A、D、E,导致COVID-19家庭聚集性疫情。结论无症状感染者是本起家庭聚集性疫情的传染源,其传染源存在隐蔽性,增加疫情防控的难度;严格筛查和管理有疫区暴露史的人员,发现无症状感染者对防止病毒在社区传播具有重要的公共卫生学意义。

Objective To analyze a family clustering of coronavirus disease 2019(COVID-19)associated with the exposure to an asymptomatic case and to provide evidences for developing strategies for COVID-19 prevention.Methods We conducted a field survey on a cluster epidemic of COVID-19 occurred between January 31 to February 6,2020 in Chenzhou city of Hunan province.Throat swab specimens of the cases were detected for novel coronavirus nucleic acid with real-time fluorescence quantitative polymerase chain reaction.Results The clustering epidemic occurred within 6 days in a family,involving 4 confirmed cases and one asymptomatic case.The first case of the clustering was 56-year old man laboratory confirmed 6 days after the onset of symptoms and the case reported no history of traveling in or contact with someone from the epidemic region.The second case was the first case's son(30 years old)without clinical symptoms but positive for novel coronavirus nucleic acid one day after the diagnosis of the first case;the third case was the son's wife,a confirmed case based on viral nucleic acid positive and lung X-ray examination but without clinical symptoms;the couple had long-term history of living and working in Wuhan city and went to their father's home during Spring Festival holiday.Other two cases of the clustering were the son's mother(52 years)and daughter(2.5 years),who had no no history of traveling in or contact with someone from the epidemic region.The family members lived together in the first case's home and did not report taking measures to prevent the disease.The family COVID-19 clustering was probably induced by exposure to the couple having no physical symptoms of the disease based on the information collected.Conclusion The family COVID-19 clustering may be induced by the exposure to an asymptomatic case,suggesting that identification of asymptomatic cases is very important for the control of COVID-19 epidemic.