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

Objective: 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. Methods: 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. Results: A total of 40 COVID-19 cases were associated with the department store exposure, accounting for 75.47 % 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 % ) and farmers (40.00 % ). The main clinical manifestations included fever (95.00 % ), cough (35.00 % ), and diarrhea (15.00 % ). The proportion of confirmed severe cases was 32.50 % . The incidence curve showed that the incidence peak occurred on 31 January, 2020. Among the 40 cases, 6(15.00 % ) were department store employees, 19 (47.50 % ) were customers and 15 (37.50 % ) 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. Conclusion: 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.