Transmission chains of clusters of COVID-19 associated with a market in Beijing
10.3760/cma.j.cn112338-20201027-01285
- VernacularTitle:北京市某市场新型冠状病毒肺炎相关聚集性疫情传播链分析
- Author:
Yamin SUN
1
;
Feng LIU
;
Wei CAI
;
Lei WANG
;
Fangyao LIU
;
Yulian LI
;
Juguang WANG
;
Huaqing YING
;
Jiye FU
Author Information
1. 北京市海淀区疾病预防控制中心 100094
- Keywords:
COVID-19;
Cluster;
Transmission chains
- From:
Chinese Journal of Epidemiology
2021;42(3):427-432
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the clusters of COVID-19 associated with a market (market Y) in Haidian District, Beijing, and analyze the chain of transmission and provide reference for effective prevention and control of COVID-19.Methods:The investigation of field epidemiology and cluster epidemic was used to describe the distributions of all COVID-19 cases. The time sequence diagram of the cases, disease onset was drawn and transmission chains were analyzed. Real-time RT-PCR assay was conducted for SARS-CoV-2 nucleic acid test by using the respiratory samples of the cases.Results:The COVID-19 epidemic, originated from a wholesale farm produce market (market X) in Fengtai District, Beijing, was introduced by a marketer in the market Y who had exposed to market X, causing 8 clusters of 20 confirmed cases of COVID-19 and one asymptomatic case, including 8 men and 13 women, in market Y, surrounding communities, food plaza, companies,families and other places. The incidence peaked during June 10-14, 2020; the median age of the cases was 45 years, ranging from 5 years to 87 years. The initial symptoms of the cases included fever (10/20) and pharynx discomfort (7/20). The median of incubation period was 5 days ( IQR:3-8). The median of serial interval between primary case and secondary cases was 5 days with a secondary attack rate of 3.7%(20/538), and the secondary attack rate in household close-contacts was 14.0% (7/50). Conclusions:The clusters of COVID-19 associated with market Y were caused by several modes of transmission, including human-to-human, contaminated material-to-human, etc. The combined public-health response measures were effective to control the COVID-19 epidemic in Haidian district of Beijing.
