LAUSR

INTRODUCTION A local outbreak of coronavirus disease 2019 (COVID-19) has rapidly evolved into a global pandemic and the number of cases and deaths has increased exponentially. In this study, we report a COVID-19 outbreak that occurred in a departmental store, between January and February 2020, in Wenzhou, China and investigated the reasons for the outbreak. METHODOLOGY An outbreak investigation was initiated after the index case was diagnosed as COVID-19. Cases (confirmed and suspected) and close contacts were defined. Their pharyngeal swabs were collected and examined with real-time polymerase chain reaction (RT-PCR) for nucleic acid. All investigations of the confirmed and suspected cases were carried out by epidemiologists and the source of infection was tracked by using big data. RESULTS Thirty-nine COVID-19 cases and one asymptomatic individual were found in this outbreak, as determined by clinical manifestations, epidemiological investigation, and RT-PCR. Majority of COVID-19 cases occurred in a departmental store, three of whom traveled to participate in a meeting held in H city. After disease outbreak in the departmental store, intra-family transmission of COVID-19 occurred in five families. Two clusters of the COVID-19 outbreak were identified. One cluster was attributed to the family party, while another was attributed to a hotel party, which was responsible for transmission across three generations, infecting five family members. CONCLUSIONS This was travel associated COVID-19 outbreak in a departmental store in Wenzhou, China. High infectivity of COVID-19 was observed. A departmental store, especially without recirculation of the air, was a high-risk site for the transmission of COVID-19. The use of big data and related information was very useful in epidemiological investigation of cases and contacts.