Objective: Analysis of clustering characteristics of coronavirus disease 2019 (COVID-19) in Guangdong Province. Methods: The COVID-19 cases in Guangdong Province onset from January 1 to February 29, 2020 were collected from Chinese information system for disease control and prevention and Emergency Public Reporting System. Obtain the epidemiological survey data of the cluster epidemic situation, and clarify the scale of cluster epidemic situation, the characteristics of the index cases, family and non-family subsequent cases. Calculate serial interval according to the onset time of the index cases and subsequent cases, secondary attack rate based on the close contacts tracking results, the characteristics of different cases in the clustered epidemic were compared. Results: A total of 283 cluster were collected, including 633 index cases, 239 subsequent cases. Families are mainly clustered, the total number involved in each cluster is in the range of 2-27, M (P25, P75) are 2.0 (2.0, 4.0). During January 15 to February 29, the secondary attack rate is 2.86% (239/8 363) in Guangdong Province, the family secondary attack rate was 4.84% (276/3 697), and the non-family secondary attack rate was 1.32% (61/4 632). According to the reporting trend of the number of cases in Guangdong Province, it can be divided into four stages, the rising stage, the high platform stage, the descending stage and the low level fluctuation period. The secondary attack rate of the four stages were 3.5% (140/3 987), 2.3% (55/2 399), 2.6% (37/1 435), 1.3% (7/542), respectively. The difference was statistically significant (P=0.003). Conclusion: COVID-19 cluster mainly occurs in families in Guangdong Province. The scale of the clustered epidemic was small; the serial interval was short; and the overall secondary attack rate was low.
目的： 分析广东省新型冠状病毒肺炎聚集性疫情特点。 方法： 从中国疾病预防控制信息系统传染病报告管理信息系统和突发公共卫生事件报告管理信息系统中，获取2020年1月1日至2月29日的广东省新型冠状病毒肺炎病例，提取聚集性疫情流行病学调查资料，明确聚集性疫情规模、引入病例、家庭与非家庭续发病例特点。根据引入病例与续发病例发病时间间隔计算代间距，根据密接追踪结果计算续发率，比较聚集性疫情中不同病例的特点。 结果： 本研究共收集283起聚集性疫情，涉及引入病例633例，续发病例239例。以家庭聚集为主，聚集性疫情涉及病例数最大值为27例，最小值为2例，M（P25，P75）为2.0（2.0，4.0）。广东省总体续发率为2.86%（239/8 363），家庭续发率为4.84%（276/3 697），非家庭续发率为1.32%（61/4 632）。根据广东省疫情特点分为疫情上升期、高平台期、下降期、低水平波动期4个阶段，4个阶段的续发率分别为3.5%（140/3 987）、2.3%（55/2 399）、2.6%（37/1 435）、1.3%（7/542），差异具有统计学意义（P=0.003）。 结论： 广东省聚集性疫情主要以家庭聚集为主，聚集疫情规模较小，病例潜伏期代间距较短，总体续发率较低。.
Keywords: COVID-19; Cluster outbreak; Epidemiology; Secondary attack rate; Serial interval.