重庆市一起新型冠状病毒肺炎家庭聚集性疫情调查分析

A survey on clustering of novel coronavirus disease in families in Fengjie county of Chongqing municipality

目的分析重庆市一起新型冠状病毒肺炎家庭聚集性疫情的流行病学特征,分析病例的感染来源,探讨其传播模式。方法于2020年2月1日至2月16日在重庆市奉节县应用现场流行病学方法调查7例确诊病例、1例无症状感染者及其密切接触者,采用RT-PCR对采集的相关标本进行新冠肺炎病毒检测。结果7例病例及1例无症状感染者来自三个家庭,其中一个家庭为武汉常住人员,返奉后三个家庭多次聚集;123名密切接触者中,确诊病例5例,病原筛查出无症状感染者1例,三个家庭内部的感染率为72.7%,其余密切接触者无异常。结论本起疫情系一起输入性引起密切接触者发生感染的家庭聚集性疫情,证实了新冠肺炎人传人的传播模式,飞沫传播和密切接触是主要传播方式,可能存在潜在的遗传易感性。

Objective To describe family clustering characteristics of novel coronavirus disease 2019(COVID-19)and to explore the transmission mode of the emerged novel coronavirus(2019-nCoV).Methods We conducted field and questionnaire surveys among 7 laboratory confirmed COVID-19 cases and an asymptomatic infection and 123 close contacts of the cases from February 1-16,2020 in Fengjie,Chongqing.All the cases'and the asymptomatic infection's throat swab specimens were viral nucleic acid positive with real-time reverse transcription PCR(RT-PCR).Results The 7 confirmed cases and an asymptomatic infection were from 3 relative families;five members of the first case's family were long-term immigrants of Wuhan city-the epicenter of the disease outbreak and histories of cohabitation and frequent home party immediately after the migrant family returning to Fengjie county from Wuhan city was reported by the members of the other two families.The first case was a 37-year old man diagnosed on February 1,2020 at Fengjie county 8 days after leaving Wuhan and 7 days after the occurrence of clinical symptoms;the man's son and the man's father and mother were diagnosed10 days and 11 days after the confirmation of the first case.One the same day of the first diagnosis,the second case-a41-year old man(the first case's brother in law)was also diagnosed 7 days after having dinners together with the first case and 4 days after the onset of symptoms;ten days after the diagnosis,the second case's father and mother were diagnosed as confirmed cases and his wife was diagnosed as a suspected case 11 days after the diagnosis of the second case.Totally 123 close contacts of the first and the second case were identified but no close contacts of other cases were reported.No COVID-19 associated clinical symptoms were observed during 14 day's medical observation among all the close contacts.The estimated infection rate among the members of the three families was 72.7%.Conclusion The study confirmed a close contact associated family cluster of novel coronavirus disease 2019 in Fengjie county Chongqing municipality and the study results suggest that droplet transmission and close contact are main transmission ways of the novel coronavirus.