Disposal of a COVID-19 outbreak caused by imported case of an Omicron variant strain / 中国热带医学

ABSTRACT

@#Abstract： Objective　To retrospectively analyze the investigation and disposal of the COVID-19 outbreak caused by the transmission of the Omicron variant in infected imported cases, and provide basis for COVID-19 outbreak management. Methods　The description epidemiological method was used to describe the COVID-19 outbreak in Sanya City from March 31 to April 15, 2022. The propagation chain was mapped and the experience gained and shortcomings identified in emergency responses were analyzed. Results　The outbreak resulted in 95 reported locally transmitted COVID-19 cases with a incubation period M(P25, P75) of 4 (3, 5) d. In the 95 cases, the proportion of cases detected through close contact screening, centralized isolation, community screening, control area screening, active treatment (examination), and key population screening were 33.68%, 22.11%, 18.95%, 12.63%, 6.32%, 4.21% and 2.11%, respectively. The epidemic spread for 6 generations, causing 5 clusters of outbreaks and 12 cases of cluster disease. The epidemic affected 12 villages/neighborhood committees, 1 bar, 1 hospital, 1 small clinic, 1 farmer's market, 1 large shopping mall and 1 restaurant in 2 districts of Sanya City. The result of gene sequencing was Omicron variant BA.1.1. Through the immediate launch of emergency plans, nucleic acid and antigen testing, controlling close contact between infected persons and close contacts, suspending indoor business sites, central urban control, and temporary suspension, COVID-19 was controlled within 16 days. Conclusions　The transmission chain of this outbreak was clear and was caused by imported cases. Strengthening the management of the pass, doing a good job in information sharing and docking, timely screening for cases, screening, pushing, controlling high-risk groups, and implementing comprehensive control measures, can effectively prevent the spread of the epidemic, providing a reference for the control of epidemic situations in relevant scenarios.