海口市一起潜伏期新型冠状病毒肺炎病例引起的聚集性疫情分析

A cluster of COVID-19 caused by a presymptomatic case in Haikou

目的调查海口市一起潜伏期新型冠状病毒肺炎(COVID-19)病例引起的聚集性疫情,为COVID-19聚集性疫情防控提供依据。方法按照《新型冠状病毒肺炎防控方案(第四版)》开展流行病学调查,收集病例的发病和诊疗经过、临床特征和现场流行病学调查资料,分析疫情传播链和病例间传播代际关系。结果该起疫情暴露39人,报告确诊病例5例和无症状感染者2例,罹患率为17.95%。7例病例年龄为40~65岁,均居住在东山镇某农场宿舍区。病例1于2020年1月28日—2月10日与澄迈县1例COVID-19确诊病例(1月28日发病)密切接触,2月13日被隔离,2月16日发病。病例2~7于1月28日—2月13日(病例1潜伏期内)与病例1共用同一水源,且每次用水前均经病例1房间外打开水井开关及1号洗手间内的水管总阀,可能接触病例1接触过的门把手、水管总阀开关,或被病例1使用过洗手间后形成的气溶胶感染,病例间通过共同生活(同住、同餐)互相传播。病例2~7发病时间均早于病例1,但发病前14 d内均无湖北省旅居史,也未接触过除病例1以外的其他确诊病例,故推断病例1为一代病例,潜伏期传播引起该起疫情。结论这是一起潜伏期COVID-19病例引起的聚集性疫情,主要通过共同生活并间接多次触摸同一物品传播,提示COVID-19潜伏期存在传染性。

Objective To investigate a cluster of coronavirus disease 2019(COVID-19)caused by latent infection in Haikou,so as to provide reference for the prevention and control of COVID-19 clusters.Methods An epidemiological investigation was conducted according to the COVID-19 Prevention and Control Program(Fourth Edition).The course of diagnosis and treatment,clinical characteristics and field investigation data were collected to analyze the transmission chain and the intergeneration between cases.Results Among 39 people involved,five confirmed cases and two asymptomatic infections were found,with an attack rate of 17.95%.The cases aged from 40 to 65 years and lived in the dormitories near the farm of Dongshan.The first case(named Case1)closely contacted with a confirmed case of COVID-19 in Chengmai from January 28 to February 10,was isolated on February13 and developed symptoms on February 16.The other six cases(Case 2 to Case 7)shared the water source with Case 1 from January 28 to February 13(within the incubation period of Case 1).They needed to open the power switch outside Case 1’s room and the water valve in Case 1’s washroom before the use of water.They might be infected by contacting the doorknob and the water valve contacted by Case 1,or by the aerosol formed after Case 1 used the washroom,then infected each other when living together.The onset of Case 2 to Case 7 was earlier than Case 1,and they had no travelling history in Hubei Province 14 days before and contacted no confirmed cases except Case 1.Therefore,Case 1 was the source of the cluster during his incubation period of COVID-19.Conclusion This was a cluster of COVID-19 due to latent transmission by living in the same area and touching the same objects indirectly,which indicated that COVID-19 was infectious in the incubation period.