Clustering epidemic characteristics of coronavirus disease 2019 in Hunan province
ZHAO Shan-lu, GAO Li-dong, LUO Kai-wei, ZHAN Zhi-fui, XIAO Jie-hua, HUANG CHAO-yang, ZENG Ge, DAI Zhi-hui, LIU Zi-yan, SUN Qian-lai, ZHANG Heng-jiao, YANG Hao, HU Shi-xiong
Hunan Provincial Center for Disease Control and Prevention, Changsha, Hunan 410005, China
Abstract：Objective To analyze the epidemiological characteristics of 195 coronavirus disease 2019 (COVID-19) clusters in Hunan province, and to provide a scientific basis for prevention and control of COVID-19 clusters. Methods Data about 195 COVID-19 clusters in Hunan province from January to February 2020 were collected to conduct descriptive epidemiological analysis. Results There were 195 COVID-19 clusters, with 696 cases and without death case. The top three cities of reported incidents were Changsha (51 clusters), Yueyang (31 clusters) and Shaoyang (22 clusters). The number of outbreaks and cases peaked on January31. Male to female sex ratio was 1.02∶1. The mean age was 44.7 years old, of which 42 (6.3%) cases were children aged below 15 years. 55 (8.28%) cases were asymptomatic. Most of the cases were mild and normal types, accounting for 79.5%. There were only 28 (14.4%) clusters occurred in first-generation cases, 154 (79.0%) in second-generation cases, 10 (5.1%) in third-generation cases and 3 (1.5%) in fourth-generation cases. The mean intergenerational interval between first-generation and second-generation cases was 6.2 days (95%CI: 5.1-7.3), with a median of 5.0 days. The secondary incidence rate of household exposure clusters ranged from 0.7% to 100%, with a median of 11.8%. The secondary incidence rate of medical institutions ranged from 0.9% to 20.0%, with a median of 6.9%. 127 (65.1%) clusters were imported from Hubei province. Among the 696 clustered cases, 268 (38.5%) were first-generation cases, 387 (55.6%) second-generation cases, 32 (4.6%) third-generation cases, and 9 (1.3%) fourth-generation cases. The incidents were exposed in various ways, including 184 cases with cohabitation exposure, 185 cases with same car exposure, 118 cases with party exposure, 149 cases with dinner exposure, 165 cases with conversation exposure, and 8 cases with conference training exposure. Conclusions COVID-19 clusters in Hunan province mainly occurred in families. It is necessary to pay attention to key areas, key populations and key places. Various prevention and control measures should be implemented to effectively deal with COVID-19 clusters and prevent further spread.
2020, Vol. 27 
