The Seroprevalence of SARS-CoV-2 in Children During Early COVID-19 Pandemic in Korea: A Nationwide, Population-Based Study

초록

Background Coronavirus disease 2019 (COVID-19) is often asymptomatic and associated with mild clinical symptoms in children. Social distancing measures have led to a relatively small number of confirmed COVID-19 cases in Korea than in other countries in the earlier pandemic phase. Previous seroprevalence studies in Korean adults before the introduction of COVID-19 vaccination campaign have shown a low antibody positivity rate. However, data on COVID-19 seroprevalence in Korean children remained scarce. In this study, we assessed the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children in Korea. Methods Between December 2020 and March 2021, stratified serum samples were collected from children aged 0–18 years in 17 different regions across the country. The SARS-CoV-2 antibody test was conducted using an electro-chemiluminescence immunoassay (ECLIA) to detect the antibodies against nucleocapsid antigens of SARS-CoV-2. Samples that tested positive using the ECLIA were reflexed to an additional plaque reduction neutralization test (PRNT) for SARS-CoV-2. Results A total of 1,887 samples were collected. Excluding 21 samples collected from regional medical centers, 1,866 samples were included in the final analysis. Two samples (0.11%) were positive for the antibodies against nucleocapsid antigens of SARS-CoV-2. Both samples were shown to have neutralizing antibodies for SARS-CoV-2 via PRNT. Conclusion After 1 year since the start of COVID-19 pandemic, the seroprevalence of SARS-CoV-2 among Korean children was 0.11%, which was lower than the adults (0.52%) in another study conducted during a similar period. In the early stages of the COVID-19 pandemic, the seroprevalence of SARS-CoV-2 in Korea was lower than those of other countries, which was presumed to be the consequence of a very strong social distancing measures.

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