宁波市一起新型冠状病毒肺炎家庭聚集性疫情调查

Investigation on a family cluster of COVID-19 in Ningbo

目的报道宁波市一起新型冠状病毒肺炎(COVID-19)家庭聚集性疫情现场流行病学调查结果,为防控COVID-19疫情提供依据。方法根据《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,收集病例的人口学信息、发病诊疗过程、临床资料和流行病学史等;对病例的密切接触者进行排查和管理;分析传染源、传播链及病例代际关系。结果该起疫情共报告12例COVID-19确诊病例和1例无症状感染者,罹患率为16.05%。男性5例,女性8例。年龄最小11岁,最大85岁,中位数为39岁。临床分型以轻型和普通型为主;潜伏期为2~13 d,中位数为6.5 d。首例病例(病例1)2020年1月22日发病,曾于1月20日近距离接触过无症状感染者张某,张某与1月19日宁波市一起佛事集会活动引起的COVID-19聚集性疫情相关。病例1于1月22—27日多次走亲访友,与24名家庭成员聚餐,导致二代和三代病例各6例。除该家族成员外的密切接触者54人,未检出感染者。结论该起COVID-19家庭聚集性疫情的传染源可能为无症状感染者,通过近距离接触感染家庭某一成员,后通过家庭聚餐和生活接触传播。

Objective To report an investigation of a family cluster of coronavirus disease 2019(COVID-19)in Ningbo,so as to provide reference for the prevention and control measures.Methods According to the COVID-19 Prevention and Control Program(fourth version),an epidemiological investigation was conducted to collect the demographic information,clinical features and exposure history,to find the close contacts,and to figure out the source and route of infection.Results Twelve confirmed cases and one asymptomatic case were reported.The attack rate was 16.05%.Among them,five were males and eight were females;the age ranged from 11 to 85 years old,with a median of 39 years old;most had mild symptoms.The incubation period was 2-13 days,with a median of 6.5 days.The first case(Case 1)developed the symptoms on January 22,and had close contact with Zhang,an asymptomatic case,on January 20.Zhang was related to a cluster in the Buddhist assembly on January 19.Case 1,who caused the spread of the epidemic among family members,participated in several family visits and dinners from January 22 to 27 with other 24 families,resulting in six secondary cases and six third-generation cases.There were 54 close contacts except the family members,no infection was found.Conclusion This family cluster may result from the close contact with an asymptomatic case,and then spread within families through having dinners and living together.