[2022 Quarantine Relaxation Period Foreign Students Entering Honam COVID-19 Epidemiological Survey Results and...

This report is an investigation of the outbreak of coronavirus disease 2019 (COVID-19) among participants in a foreign students' class program at a local Korean university in December 2022, during the relaxation period of COVID-19 prevention. It also describes the measures and analyses of 143 confirmed cases among 256 international students of Chinese nationality who entered the country during the period and four confirmed cases among 41 existing residents. The incidence was higher in men (53.8%) than in women, with 100%, 57.3%, 42.3%, and 26.3% incidences among individuals in their 50s, 30s, 40s, and 20s, respectively. Regarding vaccination, 59.1% of the participants had received the second dose and 48.7% had received the third dose or more. The incidence rate of COVID-19 for international arrivals among the investigated confirmed cases was 97.2%, and mutation analysis of these samples showed the presence of subvariants such as BA.5 61.5%, BQ.1 14.7%, and BN.1 2.3% among the Omicron subsystems; subvariant BA.2.75 or new variants were not identified. Regarding the period from the date of entry to the date of confirmation, 109 (42.6%) cases were confirmed within 10 days of passive surveillance after entering the country, of which 82 (32.0%) were confirmed within 2-3 days and were presumed to be infected before entering the country. Thirty cases were confirmed after 10 days. Furthermore, four existing arrivals had contact with confirmed positive individuals; therefore, further transmission was considered possible. Preemptive tests and thorough management were found to minimize further COVID-19 influx into the community, and the continuous monitoring of overseas outbreaks and adjustment of the strength of quarantine policies have an important impact on case management.