兰州市报告的首起新型冠状病毒肺炎家庭聚集性疫情调查

Epidemiological investigation on the first family cluster of COVID-19 in Lanzhou

目的对兰州市报告的首起新型冠状病毒肺炎(COVID-19)家庭聚集性疫情进行流行病学调查,为提高COVID-19疫情防控能力提供依据。方法2020年1月23日,兰州大学第一医院报告2例COVID-19疑似病例,参照《新型冠状病毒肺炎病例流行病学调查方案(第二版)》进行流行病学调查,收集病例基本信息、发病诊疗经过、临床症状、实验室检测、家庭环境、流行病学史、密切接触者和转归等情况,分析家庭聚集性疫情的传播链和传播代际。结果该起COVID-19家庭聚集性疫情从1月23日发现至2月21日,持续29 d,报告9例COVID-19确诊病例和1例无症状感染者,其中死亡1例。其中3例为武汉市输入病例,是该起疫情的传染源;二代病例7例,均与3例武汉市输入病例有聚餐史和(或)日常生活接触史,家庭续发率为41.18%(7/17)。9例确诊病例中,潜伏期最长10 d,最短4 d,中位数为9 d。除7例续发病例外,排查到密切接触者24人,严重急性呼吸综合征冠状病毒2型核酸检测结果均为阴性。结论兰州市报告的首起COVID-19家庭聚集性疫情由武汉市输入病例引起,通过聚餐和(或)日常生活接触在家庭内传播,传播途径为呼吸道飞沫和密切接触。

Objective To investigate the first family cluster of COVID-19 in Lanzhou,so as to provide basis for improving the COVID-19 outbreak prevention capacity.Methods On January 23,the First Hospital of Lanzhou University reported two suspected cases of COVID-19.According to the COVID-19 Epidemiological Investigation Plan(second edition),general information,disease diagnosis and treatment,clinical symptoms,laboratory test results,household environment,exposure history and close contacts were collected to figure out the source of infection and routes of transmission.Results This family cluster lasted 29 days,from January 23 to February 21,reporting nine confirmed cases(one death)and one asymptomatic case.There were three imported cases from Wuhan,who were the source of the cluster;and seven secondary cases,who all had close contact with the imported cases during daily life or through having dinners.The secondary attack rate was 41.18%(7/17).Among 9 confirmed cases,the incubation period ranged from four to ten days,with a median of nine days.Except for seven secondary cases,24 close contacts were found and detected negative in the nucleic acid tests.Conclusions The first family cluster of COVID-19 in Lanzhou is caused by the imported cases from Wuhan.All the secondary cases have had dinners and/or had contact with the imported cases,thus they are infected through respiratory droplets and close contact.