Abstract: Objective To analyze a cluster outbreak of COVID-19 associated with exposure to a shopping mall in Jinan City, investigate the possible transmission chain, and provide reference for further prevention and control. Methods An epidemiological survey was conducted on 8 COVID-19 cases associated with a shopping mall, patients family members were interviewed, and data extracted were entered into an excel database for descriptive statistical analysis. Results Of the 8 cases, 4 were employees in a shopping mall, 2 were customers, and 2 were employees family members. The average time from onset to the first visit of 5 patients was 4.8 days. The patients lived in 3 different communities. Three of the four employees worked at the same counter, and one worked on another floor in the mall. A total of 777 close contacts were identified, including 35 family members, 736 employees in the mall and 6 customers. The average number of close contacts per case was 97. Conclusion The cluster outbreak in the shopping mall involves a wide range and large number of close contacts, so it is difficult to control. COVID-19 can be transmitted from person to person, and respiratory droplets and close contact are the major ways of transmission. During COVID-19 epidemic, due attention should be paid to employee’ health declaration and sick leave in order to avoid transmission in work place.

Key words: COVID-19, Cluster outbreak, Close contacts, Transmission chain