Objective To investigate the epidemiological characteristics, pathogenesis and clinical outcomes of asymptomatic patients with coronavirus disease 2019 (COVID-19), and we provide theoretical basis for the formulation of epidemic prevention and control strategies.
Methods Follow-up survey of 32 asymptomatic carriers with COVID-19 were conducted in Liaoning Province. Demographic information, contact with confirmed cases, diagnosis time, clinical outcomes, etc were collected through the Chinese Disease Control and Prevention Information System-Infectious Disease Monitoring and Public Health Emergency Monitoring System.
Results Of the 32 asymptomatic patients reported, 28 cases were the close contacts. 20 cases(62.5%) were confirmed, and the clinical outcomes were mainly general and mild type (95.0%); 27 cases (84.37%) were clustered in families. The median time from diagnosis to confirmed cases was 2 days, the longest interval was 11 days, the shortest was the very day; The duration of infection ranged from 5 to 27 days, with a median of 16 days. Epidemiological evidence of four chains of transmission suggests incubation period transmission.
Conclusion The condition of asymptomatic carriers with COVID-19 in our province is mild after being converted to confirmed cases, but the communicable period is relatively long, and most of them are family clustering. It is urgent to monitor the close contacts through multiple nucleic acid screening to control the potential outbreaks.
摘要： 目的 探讨新冠肺炎无症状感染者流行病学特征、发病进程及临床结局，为制定疫情防控策略提供理论依 据。 方法 对辽宁省 32 例新冠肺炎无症状感染者追踪调查，通过中国疾病预防控制信息系统-传染病监测、突发公共 卫生事件监测系统及流行病学调查报告收集人口学信息、接触情况、诊断时间、临床转归情况等。 结果 累计报告的 32 例无症状感染者中，28 例为辽宁省报告确诊病例的密切接触者，20 例(62.5%)转为确诊病例，临床结局以普通型、轻 型为主(95.0%)；27 例(84.37%)为家庭聚集性发病。无症状感染者诊断至转为确诊病例的中位时间为 2 d，最长 11 d， 最短当日；传染期的范围 5~27 d，中位时间为 16 d。有 4 个传播链的流行病学证据提示为潜伏期传播。 结论 辽宁省 无症状感染者转为确诊病例病情轻微，但传染期较长，多为家庭聚集性发病。亟待通过核酸筛查严格监控密切接触 者，以控制潜在疫情暴发。