PHWR Public Health Weekly Report

This report aimed to analyze confirmed cases of coronavirus disease 2019 (COVID-19) among imported cases at the Incheon Airport National Quarantine Station (IANQS) and to report on their epidemiological characteristics and trends while under quarantine.
In 2021, among the 11,961 imported COVID-19 cases, 1,287 (10.8%), excluding those confirmed via air ambulance, were confirmed through quarantine at the IANQS. Of these, 849 (66.0%) were male and 616 (47.9%) were in their 20s and 30s. Approximately 76.2% of the cases were Korean nationals.
According to the findings, approximately 19.3% of the cases were observed in June due to an increase in imported cases from Indonesia while, the number of imported cases gradually decreased to 2.8% in November. An analysis of the quarterly distribution of confirmed cases showed the highest number (n=420) in the third quarter and a rapid decrease in the fourth quarter (n=124). The decrease in confirmed cases was attributed to the reduced number of patients with symptoms and quarantine targets who were subjected to testing, from 2,941 in January to 1,000 in March and less than 1,000 after August. Among the 14,977 symptomatic cases and quarantine targets, 1,263 were confirmed (8.4%). Only 860 (66.8%) of 1,287 total confirmed cases were symptomatic. An additional 261 (20.3%) showed unrecognized fever during quarantine without reporting symptoms and 166 (12.9%) were asymptomatic. Among foreign nationals, 169 cases of unrecognized fever were reported, more than twice the 78 confirmed symptomatic cases.
In summation, the new COVID-19 variants and increased vaccination rates led to changes in the overall quarantine situation and the number of COVID-19 cases confirmed during quarantine in 2021. Analysis of these epidemiological characteristics is expected to povide reference data for future quarantine responses.

Key words Coronavirus disease 2019 (COVID-19), Quarantine, Airport

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