{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T22:53:28Z","timestamp":1790981608895,"version":"4.1.0"},"reference-count":19,"publisher":"Ovid Technologies (Wolters Kluwer Health)","content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"abstract":"<jats:sec>\n                    <jats:title>Background:<\/jats:title>\n                    <jats:p>While children were initially less susceptible to coronavirus disease 2019 (COVID-19), emerging variants and eased public health measures shifted the burden to younger populations. This study characterizes pediatric COVID-19 features in South Korea across 7 epidemic waves, evaluating vaccination and comorbidities on disease severity.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>This retrospective study used the national K-COV-N database, integrating surveillance and health insurance claims data. Children 1\u201317 years old with confirmed COVID-19 from January 2020 to August 2023 were included. Participants were stratified by age and dominant variant waves. Logistic regression assessed demographic and clinical risk factors for severity.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>Among 239,334 cases, the Omicron-dominant era (waves 5\u20137) accounted for 97.88% of the total burden. Although the mean hospital stay decreased from 12.6 days (wave 1) to 3.7 days (wave 5), mortality and multisystem inflammatory syndrome in children were concentrated during Omicron waves. Children 1\u20134 years of age experienced the most severe outcomes. Multivariate analysis identified cardiovascular disease (adjusted odds ratio [AOR]: 3.97), neurologic disorders (AOR: 2.88) and obesity (AOR: 2.68) as significant independent risk factors for severity. After adjusting for age and sex, vaccination showed limited protective effects against severe outcomes in this cohort.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions:<\/jats:title>\n                    <jats:p>The pediatric COVID-19 landscape in South Korea shifted to massive community transmission during the Omicron era. While individual clinical severity declined, the absolute burden remained significant due to high prevalence. Future outbreak mitigation requires targeted protection for high-risk groups and scalable healthcare planning.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1097\/inf.0000000000005271","type":"journal-article","created":{"date-parts":[[2026,6,16]],"date-time":"2026-06-16T22:06:22Z","timestamp":1781647582000},"update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":0,"title":["Burden of COVID-19 in Korean Children: A Retrospective Observational Study Using Real-world Data"],"prefix":"10.1097","author":[{"given":"Young Hwa","family":"Lee","sequence":"first","affiliation":[{"name":"Allergy and Immunology Center, Korea University, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eunseon","family":"Gwak","sequence":"additional","affiliation":[{"name":"Department of Preventive Medicine"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2733-0715","authenticated-orcid":false,"given":"Young June","family":"Choe","sequence":"additional","affiliation":[{"name":"Allergy and Immunology Center, Korea University, Seoul, Republic of Korea"},{"name":"Department of Pediatrics, Korea University College of Medicine, Seoul, Republic of Korea."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2026,6,17]]},"reference":[{"key":"R1-20261002","doi-asserted-by":"crossref","first-page":"280","DOI":"10.1016\/S2352-4642(22)00060-8","article-title":"SARS-CoV-2 spread and hospitalisations in paediatric patients during the omicron surge.","volume":"6","author":"Belay","year":"2022","journal-title":"Lancet Child Adolesc Health"},{"key":"R2-20261002","doi-asserted-by":"crossref","first-page":"e066809","DOI":"10.1136\/bmj-2021-066809","article-title":"Healthcare use in 700 000 children and adolescents for six months after Covid-19: before and after register based cohort study.","volume":"376","author":"Magnusson","year":"2022","journal-title":"BMJ"},{"key":"R4-20261002","doi-asserted-by":"crossref","first-page":"e13","DOI":"10.3346\/jkms.2022.37.e13","article-title":"Analysis of critical COVID-19 cases among children in Korea.","volume":"37","author":"Lee","year":"2022","journal-title":"J Korean Med Sci"},{"key":"R5-20261002","doi-asserted-by":"crossref","first-page":"e21","DOI":"10.3346\/jkms.2023.38.e21","article-title":"Pediatric deaths associated with coronavirus disease 2019 (COVID-19) in Korea.","volume":"38","author":"Shin","year":"2023","journal-title":"J Korean Med Sci"},{"key":"R6-20261002","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1186\/s13690-025-01509-3","article-title":"Impact of underlying diseases and complications on COVID-19 mortality in South Korea: analysis of national health insurance service data.","volume":"83","author":"Lee","year":"2025","journal-title":"Arch Public Health"},{"key":"R7-20261002","first-page":"2147","article-title":"Introduction to the research results of coronavirus disease 2019 big data (K-COV-N) and the corresponding utilization plan.","volume":"17","author":"Lee","year":"2024","journal-title":"Jugan Geongang Gwa Jilbyeong"},{"key":"R9-20261002","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1038\/s41586-021-03944-y","article-title":"SARS-CoV-2 B.1.617.2 delta variant replication and immune evasion.","volume":"599","author":"Mlcochova","year":"2021","journal-title":"Nature"},{"key":"R10-20261002","doi-asserted-by":"crossref","first-page":"e361","DOI":"10.1093\/cid\/ciac275","article-title":"Coronavirus disease 2019 disease severity in children infected with the omicron variant.","volume":"75","author":"Butt","year":"2022","journal-title":"Clin Infect 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Sci"},{"key":"R14-20261002","doi-asserted-by":"crossref","first-page":"e137","DOI":"10.1097\/INF.0000000000003043","article-title":"Risk factors for severe COVID-19 in children.","volume":"40","author":"Graff","year":"2021","journal-title":"Pediatr Infect Dis J"},{"key":"R15-20261002","doi-asserted-by":"crossref","first-page":"90","DOI":"10.1007\/s12016-022-08921-5","article-title":"Risk and protective factors for COVID-19 morbidity, severity, and mortality.","volume":"64","author":"Zhang","year":"2023","journal-title":"Clin Rev Allergy Immunol"},{"key":"R16-20261002","doi-asserted-by":"crossref","first-page":"667","DOI":"10.1016\/j.vaccine.2020.11.078","article-title":"Epidemiology of COVID-19 infection in young children under five years: a systematic review and meta-analysis.","volume":"39","author":"Bhuiyan","year":"2021","journal-title":"Vaccine"},{"key":"R17-20261002","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1093\/jpids\/piad116","article-title":"Guidance for prevention and management of COVID-19 in children and adolescents: a consensus statement from the pediatric infectious diseases society pediatric COVID-19 therapies taskforce.","volume":"13","author":"Willis","year":"2024","journal-title":"J Pediatric Infect Dis Soc"},{"key":"R18-20261002","doi-asserted-by":"crossref","first-page":"e303","DOI":"10.3346\/jkms.2022.37.e303","article-title":"SARS-CoV-2-Na\u00efve Korean children and adolescents hospitalized with COVID-19 in 2021.","volume":"37","author":"Choi","year":"2022","journal-title":"J Korean Med Sci"},{"key":"R19-20261002","doi-asserted-by":"crossref","first-page":"e002391","DOI":"10.1136\/bmjpo-2023-002391","article-title":"Universal versus risk-based strategies for vaccinating children against COVID-19: Japan and Korea.","volume":"8","author":"Choe","year":"2024","journal-title":"BMJ Paediatr Open"},{"key":"R20-20261002","doi-asserted-by":"crossref","first-page":"200160","DOI":"10.1016\/j.jpedcp.2025.200160","article-title":"Physician practices, attitudes, and challenges related to pediatric COVID-19 vaccination in the United States.","volume":"17","author":"Kang","year":"2025","journal-title":"J Pediatr Clin Pract"},{"key":"R21-20261002","doi-asserted-by":"crossref","first-page":"e2023004","DOI":"10.4178\/epih.e2023004","article-title":"Parental concerns about COVID-19 vaccine safety and hesitancy in Korea: implications for vaccine communication.","volume":"45","author":"Cho","year":"2022","journal-title":"Epidemiol Health"}],"container-title":["Pediatric Infectious Disease 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