[Investigation and analysis on characteristics of a cluster of COVID-19 associated with exposure in a department store in Tianjin].

Abstract

<b>Objective:</b> To describe the epidemiological characteristics of a cluster of COVID-19 cases reported in Baodi district of Tianjin as of 18 February, 2020, which might be associated with the exposure in a local department store, and provide suggestions for prevention and control strategy development. <b>Methods:</b> The basic characteristics, time and area distributions, clinical manifestations, epidemiological history and transmission mode of the COVID-19 cases associated with the department store exposure were analyzed. <b>Results:</b> A total of 40 COVID-19 cases were associated with the department store exposure, accounting for 75.47<i>%</i> of the total confirmed cases (53 cases) reported in Baodi district. The cases were mainly at the age of 60 years or older (35.00<i>%</i>) and farmers (40.00<i>%</i>). The main clinical manifestations included fever (95.00<i>%</i>), cough (35.00<i>%</i>), and diarrhea (15.00<i>%</i>). The proportion of confirmed severe cases was 32.50<i>%</i>. The incidence curve showed that the incidence peak occurred on 31 January, 2020. Among the 40 cases, 6(15.00<i>%</i>) were department store employees, 19 (47.50<i>%</i>) were customers and 15 (37.50<i>%</i>) were close contacts (secondary cases). The first case occurred on 21 January, 2020, this case was a department store employee who had a purchasing history at whole sale markets in other provinces and cities before the onset, and 3 employees were still on duty after symptom onsets. The median of the incubation period of customer cases was 6 days, and the median of the interval between onset and medical treatment of customer cases was 7 days. <b>Conclusion:</b> This was a cluster epidemic of COVID-19, which might be associated with the exposure in the department store. By now, the current prevention and control measures have achieved satisfied effects.