{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,31]],"date-time":"2026-03-31T03:32:21Z","timestamp":1774927941961,"version":"3.50.1"},"reference-count":29,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,1,20]],"date-time":"2026-01-20T00:00:00Z","timestamp":1768867200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Technology Innovation Program of the Ministry of Trade, Industry, and Energy","award":["20018111"],"award-info":[{"award-number":["20018111"]}]},{"DOI":"10.13039\/501100008005","name":"Yonsei University College of Medicine","doi-asserted-by":"publisher","award":["6-2024-0099"],"award-info":[{"award-number":["6-2024-0099"]}],"id":[{"id":"10.13039\/501100008005","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100008005","name":"Yonsei University College of Medicine","doi-asserted-by":"publisher","award":["2025-32-0027"],"award-info":[{"award-number":["2025-32-0027"]}],"id":[{"id":"10.13039\/501100008005","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>The COVID-19 pandemic and subsequent non-pharmaceutical interventions (NPIs) significantly disrupted the epidemiology of pediatric respiratory viruses. This study compared infection patterns among 3658 hospitalized children in South Korea during the pandemic (2020\u20132022) and the post-emergency phase (2023\u20132024), following the relaxation of mandatory NPIs. Of 4419 eligible tests, the most frequently detected viruses overall were rhinovirus\/enterovirus (HRV\/HEV) (27.9%), influenza (14.5%), and respiratory syncytial virus (RSV, 11.9%). The post-emergency phase was marked by a dramatic surge in influenza virus (IFV), which surged dramatically (5.5% \u2192 28.2%), and a more than two-fold increase in adenovirus (ADV) (5.7% \u2192 12.5%) (p &lt; 0.001). (p &lt; 0.001). Conversely, parainfluenza virus (PIV) detection rates declined significantly (15.4% \u2192 11.3%, p &lt; 0.001). Demographically, post-emergency phase patients were significantly older (mean 4.9 vs. 3.5 years) and experienced a shorter hospital stays (3.2 vs. 4.3 days) (p &lt; 0.001). Crucially, age-specific susceptibility shifts were evident. IFV rebounded across all pediatric ages but spiked severely in school-aged children and adolescents, while HRV\/HEV demonstrated a clear proportional shift towards older age groups. These results demonstrate a substantial reconfiguration of the pediatric respiratory landscape, necessitating age-stratified surveillance and flexible public health strategies to mitigate the future infectious disease burden.<\/jats:p>","DOI":"10.3390\/v18010130","type":"journal-article","created":{"date-parts":[[2026,1,20]],"date-time":"2026-01-20T14:57:58Z","timestamp":1768921078000},"page":"130","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Changing Trends of Respiratory Viruses in Hospitalized Children During and After the COVID-19 Emergency Phase in Yongin, South Korea (2020\u201322 vs. 2023\u201324)"],"prefix":"10.3390","volume":"18","author":[{"given":"Joon-sik","family":"Choi","sequence":"first","affiliation":[{"name":"Department of Pediatrics, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eun Gyeong","family":"Seol","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin-si 16995, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ji Hyun","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Hospital Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin-si 16995, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Heejung","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin-si 16995, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kyung Min","family":"Choi","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin-si 16995, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5634-9709","authenticated-orcid":false,"given":"Min Jung","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin-si 16995, Republic of Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"e137","DOI":"10.1093\/infdis\/jiaf212","article-title":"Pediatric Acute Respiratory Virus Hospitalizations: A Population-Based Cohort Study, 2017\u20132024","volume":"232","author":"Fitzpatrick","year":"2025","journal-title":"J. Infect. Dis."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1016\/S0140-6736(03)12162-9","article-title":"The common cold","volume":"361","author":"Heikkinen","year":"2003","journal-title":"Lancet"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"946","DOI":"10.1016\/S0140-6736(17)30938-8","article-title":"Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in young children in 2015: A systematic review and modelling study","volume":"390","author":"Shi","year":"2017","journal-title":"Lancet"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Pitzer, V.E., Viboud, C., Alonso, W.J., Wilcox, T., Metcalf, C.J., Steiner, C.A., Haynes, A.K., and Grenfell, B.T. (2015). Environmental drivers of the spatiotemporal dynamics of respiratory syncytial virus in the United States. PLoS Pathog., 11.","DOI":"10.1371\/journal.ppat.1004591"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Almeida, T., Guimar\u00e3es, J.T., and Rebelo, S. (2023). Epidemiological Changes in Respiratory Viral Infections in Children: The Influence of the COVID-19 Pandemic. Viruses, 15.","DOI":"10.3390\/v15091880"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3481","DOI":"10.1111\/ajt.16049","article-title":"Changes in influenza and other respiratory virus activity during the COVID-19 pandemic\u2014United States, 2020\u20132021","volume":"21","author":"Olsen","year":"2021","journal-title":"Am. J. Transplant."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"e70522","DOI":"10.1002\/jmv.70522","article-title":"Impact of Nonpharmaceutical Interventions During the COVID-19 Pandemic on the Epidemiology and Seasonal Patterns of Acute Respiratory Infections in Children","volume":"97","author":"Zheng","year":"2025","journal-title":"J. Med. Virol."},{"key":"ref_8","first-page":"100015","article-title":"The impact of the COVID-19 pandemic on influenza, respiratory syncytial virus, and other seasonal respiratory virus circulation in Canada: A population-based study","volume":"1","author":"Groves","year":"2021","journal-title":"Lancet Reg. Health-Am."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"e44","DOI":"10.1016\/S2352-4642(21)00333-3","article-title":"Respiratory syncytial virus: Paying the immunity debt with interest","volume":"5","author":"Hatter","year":"2021","journal-title":"Lancet Child Adolesc. Health"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Munro, A.P.S., and House, T. (2024). Cycles of susceptibility: Immunity debt explains altered infectious disease dynamics post-pandemic. Clin. Infect. Dis., ciae493.","DOI":"10.1093\/cid\/ciae493"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"r1733","DOI":"10.1136\/bmj.r1733","article-title":"Why scientists are rethinking the immune effects of SARS-CoV-2","volume":"390","author":"Tsergas","year":"2025","journal-title":"BMJ"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"111153","DOI":"10.1016\/j.envres.2021.111153","article-title":"COVID-19 and heat waves: New challenges for healthcare systems","volume":"198","author":"Daanen","year":"2021","journal-title":"Environ. Res."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Filip, R., Gheorghita Puscaselu, R., Anchidin-Norocel, L., Dimian, M., and Savage, W.K. (2022). Global Challenges to Public Health Care Systems during the COVID-19 Pandemic: A Review of Pandemic Measures and Problems. J. Pers. Med., 12.","DOI":"10.3390\/jpm12081295"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"24","DOI":"10.14776\/piv.2020.27.e11","article-title":"Guidelines for Coronavirus Disease 2019 Response in Children and Adolescents","volume":"27","author":"Kim","year":"2020","journal-title":"Pediatr. Infect. Vaccine"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2655","DOI":"10.1007\/s10096-025-05222-5","article-title":"The impact of COVID-19 pandemic on the etiological spectrum of respiratory infections in children","volume":"44","author":"Wang","year":"2025","journal-title":"Eur. J. Clin. Microbiol. Infect. Dis."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"641","DOI":"10.3201\/eid2702.204041","article-title":"COVID-19 and Infant Hospitalizations for Seasonal Respiratory Virus Infections, New Zealand, 2020","volume":"27","author":"Trenholme","year":"2021","journal-title":"Emerg. Infect. Dis."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"e346","DOI":"10.3346\/jkms.2021.36.e346","article-title":"Importation and Transmission of SARS-CoV-2 B.1.1.529 (Omicron) Variant of Concern in Korea, November 2021","volume":"36","author":"Lee","year":"2021","journal-title":"J. Korean Med. Sci."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"e171","DOI":"10.3346\/jkms.2024.39.e171","article-title":"Epidemiology of Respiratory Viruses in Korean Children Before and After the COVID-19 Pandemic: A Prospective Study from National Surveillance System","volume":"39","author":"Cho","year":"2024","journal-title":"J. Korean Med. Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"e2829","DOI":"10.1093\/cid\/ciaa1906","article-title":"The Interseasonal Resurgence of Respiratory Syncytial Virus in Australian Children Following the Reduction of Coronavirus Disease 2019-Related Public Health Measures","volume":"73","author":"Foley","year":"2021","journal-title":"Clin. Infect. Dis."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2884","DOI":"10.1038\/s41467-022-30485-3","article-title":"Off-season RSV epidemics in Australia after easing of COVID-19 restrictions","volume":"13","author":"Eden","year":"2022","journal-title":"Nat. Commun."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"ofae601","DOI":"10.1093\/ofid\/ofae601","article-title":"Burden of Illness Associated with Respiratory Syncytial Virus, Influenza, and Coronavirus Disease 2019 in Infants and Young Children in Ontario, Canada, 2018\u20132023: A Population-Based Canadian Immunization Research Network Study","volume":"11","author":"Jorgensen","year":"2024","journal-title":"Open Forum Infect. Dis."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1933","DOI":"10.3201\/eid2608.201229","article-title":"Decreased Influenza Incidence under COVID-19 Control Measures, Singapore","volume":"26","author":"Soo","year":"2020","journal-title":"Emerg. Infect. Dis."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Quintero-Salgado, E., Briseno-Ram\u00edrez, J., Vega-Cornejo, G., Damian-Negrete, R., Rosales-Chavez, G., and De Arcos-Jim\u00e9nez, J.C. (2024). Seasonal Shifts in Influenza, Respiratory Syncytial Virus, and Other Respiratory Viruses After the COVID-19 Pandemic: An Eight-Year Retrospective Study in Jalisco, Mexico. Viruses, 16.","DOI":"10.20944\/preprints202411.1855.v1"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"e70530","DOI":"10.1002\/jmv.70530","article-title":"Atypical Influenza A(H3N2) Activity Patterns in Germany, 2021\u20132023, and Characterization of Newly Emerged Virus Clades","volume":"97","author":"Duwe","year":"2025","journal-title":"J. Med. Virol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"e423","DOI":"10.1097\/INF.0000000000002845","article-title":"Effect of Social Distancing Due to the COVID-19 Pandemic on the Incidence of Viral Respiratory Tract Infections in Children in Finland During Early 2020","volume":"39","author":"Kuitunen","year":"2020","journal-title":"Pediatr. Infect. Dis. J."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"280","DOI":"10.1186\/s12985-025-02901-9","article-title":"Epidemiology and clinical characteristics of human rhinovirus in hospitalized children and adolescents with acute respiratory infections: A longitudinal study in Shenzhen, China (2019\u20132024)","volume":"22","author":"Liu","year":"2025","journal-title":"Virol. J."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"e68058","DOI":"10.2196\/68058","article-title":"Shifts in Influenza and Respiratory Syncytial Virus Infection Patterns in Korea After the COVID-19 Pandemic Resulting From Immunity Debt: Retrospective Observational Study","volume":"11","author":"Park","year":"2025","journal-title":"JMIR Public Health Surveill."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"436","DOI":"10.1111\/irv.12255","article-title":"Clinical severity of rhinovirus\/enterovirus compared to other respiratory viruses in children","volume":"8","author":"Asner","year":"2014","journal-title":"Influenza Other Respir. Viruses"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"615","DOI":"10.1007\/s00431-025-06218-1","article-title":"Dynamics of RSV hospitalization rates in \u22642-year-old children between 2020\u20132023 in Europe","volume":"184","author":"Wildenbeest","year":"2025","journal-title":"Eur. J. Pediatr."}],"container-title":["Viruses"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1999-4915\/18\/1\/130\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,22]],"date-time":"2026-01-22T05:17:20Z","timestamp":1769059040000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1999-4915\/18\/1\/130"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,20]]},"references-count":29,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,1]]}},"alternative-id":["v18010130"],"URL":"https:\/\/doi.org\/10.3390\/v18010130","relation":{},"ISSN":["1999-4915"],"issn-type":[{"value":"1999-4915","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,20]]}}}