{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T05:43:25Z","timestamp":1791179005841,"version":"4.1.0"},"reference-count":28,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2025,5,29]],"date-time":"2025-05-29T00:00:00Z","timestamp":1748476800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Korea University College of Medicine","award":["Q2204881"],"award-info":[{"award-number":["Q2204881"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>After the transition of coronavirus disease 2019 (COVID-19) from a pandemic to an endemic phase, data on respiratory viral infections remain limited. This study compared the clinical outcomes of SARS-CoV-2, influenza virus (INFV), and respiratory syncytial virus (RSV) infections and investigated how underlying medical conditions influence disease severity. During Omicron subvariant dominant periods, we conducted a multicenter, retrospective cohort study including laboratory-confirmed cases of SARS-CoV-2, INFV, and RSV infections in hospitalized patients aged \u2265 19 years. We compared demographic characteristics and clinical outcomes and analyzed the association between underlying comorbidities and severity of infection. A total of 1850 cases with SARS-CoV-2, 98 with INFV, and 63 with RSV infections were analyzed. Notable differences in the occurrence of fever, cough, sputum, and dyspnea were observed among patients with the three different viral infections. Pneumonia was diagnosed more frequently in patients with RSV infection (65.6%) compared to those with INFV infection (42.9%) and SARS-CoV-2 (34.4%) (p &lt; 0.01). For patients with SARS-CoV-2 infection, the risk of pneumonia increased by 47% in the moderate-risk group and 37% in the high-risk group. Among hospitalized patients, pneumonia was more frequently identified in patients with RSV infection, with statistical significance. Furthermore, the presence of medical conditions significantly increased the risk of developing pneumonia.<\/jats:p>","DOI":"10.3390\/pathogens14060543","type":"journal-article","created":{"date-parts":[[2025,5,29]],"date-time":"2025-05-29T06:25:04Z","timestamp":1748499904000},"page":"543","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Severity of Respiratory Viral Diseases and the Impacts of Underlying Medical Conditions During the Omicron Subvariant Dominant Epidemics\u2014A Comparative Study of SARS-CoV-2, Influenza Virus and Respiratory Syncytial Virus"],"prefix":"10.3390","volume":"14","author":[{"given":"Yu Jung","family":"Choi","sequence":"first","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Guro Hospital, Korea University College of Medicine, Seoul 08308, Republic of Korea"},{"name":"Vaccine Innovation Center-KU Medicine (VIC-K), Seoul 02841, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0148-7194","authenticated-orcid":false,"given":"Joon Young","family":"Song","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Guro Hospital, Korea University College of Medicine, Seoul 08308, Republic of Korea"},{"name":"Vaccine Innovation Center-KU Medicine (VIC-K), Seoul 02841, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seong-Heon","family":"Wie","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, St. Vincent\u2019s Hospital, College of Medicine, The Catholic University of Korea, Suwon 06591, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5874-4764","authenticated-orcid":false,"given":"Won Suk","family":"Choi","sequence":"additional","affiliation":[{"name":"Vaccine Innovation Center-KU Medicine (VIC-K), Seoul 02841, Republic of Korea"},{"name":"Division of Infectious Diseases, Department of Internal Medicine, Ansan Hospital, Korea University College of Medicine, Ansan 02841, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jacob","family":"Lee","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul 05355, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7862-5519","authenticated-orcid":false,"given":"Jin-Soo","family":"Lee","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Inha University School of Medicine, Incheon 22332, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2120-6265","authenticated-orcid":false,"given":"Young Keun","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Yonsei University, Wonju College of Medicine, Wonju 26426, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shin Woo","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 41404, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2093-3628","authenticated-orcid":false,"given":"Sun Hee","family":"Lee","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Pusan National University School of Medicine, Pusan 50612, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kyung-Hwa","family":"Park","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Chonnam National University Medical School, Gwangju 61469, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1063-8476","authenticated-orcid":false,"given":"Hye Won","family":"Jeong","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, Chungbuk National University College of Medicine, Cheongju 28644, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3283-1880","authenticated-orcid":false,"given":"Jin Gu","family":"Yoon","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Guro Hospital, Korea University College of Medicine, Seoul 08308, Republic of Korea"},{"name":"Vaccine Innovation Center-KU Medicine (VIC-K), Seoul 02841, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hye","family":"Seong","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Guro Hospital, Korea University College of Medicine, Seoul 08308, Republic of Korea"},{"name":"Vaccine Innovation Center-KU Medicine (VIC-K), Seoul 02841, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eliel","family":"Nham","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Guro Hospital, Korea University College of Medicine, Seoul 08308, Republic of Korea"},{"name":"Vaccine Innovation Center-KU Medicine (VIC-K), Seoul 02841, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ji Yun","family":"Noh","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Guro Hospital, Korea University College of Medicine, Seoul 08308, Republic of Korea"},{"name":"Vaccine Innovation Center-KU Medicine (VIC-K), Seoul 02841, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hee Jin","family":"Cheong","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Guro Hospital, Korea University College of Medicine, Seoul 08308, Republic of Korea"},{"name":"Vaccine Innovation Center-KU Medicine (VIC-K), Seoul 02841, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4546-3880","authenticated-orcid":false,"given":"Woo Joo","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Guro Hospital, Korea University College of Medicine, Seoul 08308, Republic of Korea"},{"name":"Vaccine 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(2021). Disappearance of seasonal respiratory viruses in children under two years old during COVID-19 pandemic: A monocentric retrospective study in Milan, Italy. Front. Pediatr., 9.","DOI":"10.3389\/fped.2021.721005"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1186\/s12985-021-01627-8","article-title":"Impact of COVID-19 pandemic on the prevalence of respiratory viruses in children with lower respiratory tract infections in China","volume":"18","author":"Liu","year":"2021","journal-title":"Virol. J."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1016\/j.ijid.2021.12.358","article-title":"SARS-CoV-2 infection in children in Moscow in 2020: Clinical features and impact on circulation of other respiratory viruses: SARS-CoV-2 infection in children in Moscow in 2020","volume":"116","author":"Yakovlev","year":"2022","journal-title":"Int. J. Infect. Dis."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1990","DOI":"10.1002\/jmv.27570","article-title":"Epidemiological changes of common respiratory viruses in children during the COVID-19 pandemic","volume":"94","author":"Ye","year":"2022","journal-title":"J. Med. Virol."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Zeng, Z., Guan, W., Liu, Y., Lin, Z., Liang, W., Liang, J., Chen, B., Wu, T., Wang, Y., and Yang, C. (2021). Different circulation pattern of multiple respiratory viruses in southern China during the COVID-19 pandemic. Front. Microbiol., 12.","DOI":"10.3389\/fmicb.2021.801946"},{"key":"ref_6","first-page":"597","article-title":"Sentinel surveillance results for influenza and acute respiratory infections during the coronavirus disease 2019 pandemic","volume":"16","author":"Cha","year":"2023","journal-title":"Public Health Wkly. Rep."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"703","DOI":"10.1016\/j.ccm.2018.07.005","article-title":"Influenza and viral pneumonia","volume":"39","author":"Cavallazzi","year":"2018","journal-title":"Clin. Chest Med."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"923","DOI":"10.1164\/ajrccm.160.3.9901107","article-title":"Severe community-acquired pneumonia: Risk factors and follow-up epidemiology","volume":"160","author":"Ruiz","year":"1999","journal-title":"Am. J. Respir. Crit. Care Med."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"373S","DOI":"10.1378\/chest.119.2_suppl.373S","article-title":"III. Hospital-acquired pneumonia: Risk factors, microbiology, and treatment","volume":"119","author":"Lynch","year":"2001","journal-title":"Chest"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"699","DOI":"10.1007\/s15010-015-0801-y","article-title":"Influence of chronic illnesses and underlying risk conditions on the incidence of pneumococcal pneumonia in older adults","volume":"43","author":"Gomez","year":"2015","journal-title":"Infection"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"e8429","DOI":"10.1097\/MD.0000000000008429","article-title":"Disease burden of hospitalized community-acquired pneumonia in South Korea: Analysis based on age and underlying medical conditions","volume":"96","author":"Choi","year":"2017","journal-title":"Medicine"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Liang, C., Begier, E., Hagel, S., Ankert, J., Wang, L., Schwarz, C., Bayer, L.J., von Eiff, C., Liu, Q., and Southern, J. (2024). Estimated Incidence of respiratory syncytial virus (RSV)-related Hospitalizations for acute respiratory infections (ARIs), including community acquired pneumonia (CAP), in Adults in Germany. medRxiv, medRxiv:06.09.24308507.","DOI":"10.1101\/2024.06.09.24308507"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1111\/irv.12910","article-title":"Estimating the burden of adult hospital admissions due to RSV and other respiratory pathogens in England","volume":"16","author":"Sharp","year":"2022","journal-title":"Influenza Other Respir. Viruses"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Fleming, D.M., Taylor, R.J., Lustig, R.L., Schuck-Paim, C., Haguinet, F., Webb, D.J., Logie, J., Matias, G., and Taylor, S. (2015). Modelling estimates of the burden of respiratory syncytial virus infection in adults and the elderly in the United Kingdom. BMC Infect. Dis., 15.","DOI":"10.1186\/s12879-015-1218-z"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"m1966","DOI":"10.1136\/bmj.m1966","article-title":"Factors associated with hospital admission and critical illness among 5279 people with coronavirus disease 2019 in New York City: Prospective cohort study","volume":"369","author":"Petrilli","year":"2020","journal-title":"BMJ"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Izcovich, A., Ragusa, M.A., Tortosa, F., Lavena Marzio, M.A., Agnoletti, C., Bengolea, A., Ceirano, A., Espinosa, F., Saavedra, E., and Sanguine, V. (2020). Prognostic factors for severity and mortality in patients infected with COVID-19: A systematic review. PLoS ONE, 15.","DOI":"10.1101\/2020.04.08.20056598"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"e13341","DOI":"10.1111\/irv.13341","article-title":"How does the burden of respiratory syncytial virus compare to influenza in Spanish adults?","volume":"18","author":"Gutierrez","year":"2024","journal-title":"Influenza Other Respir. Viruses"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1086\/380907","article-title":"Risk factors for severe respiratory syncytial virus infection in elderly persons","volume":"189","author":"Walsh","year":"2004","journal-title":"J. Infect. Dis."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Mart\u00ednez, A., Soldevila, N., Romero-Tamarit, A., Torner, N., Godoy, P., Rius, C., Jan\u00e9, M., Dom\u00ednguez, \u00c0., and Surveillance of Hospitalized Cases of Severe Influenza in Catalonia Working Group (2019). Risk factors associated with severe outcomes in adult hospitalized patients according to influenza type and subtype. PLoS ONE, 14.","DOI":"10.1371\/journal.pone.0210353"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"f5061","DOI":"10.1136\/bmj.f5061","article-title":"Populations at risk for severe or complicated influenza illness: Systematic review and meta-analysis","volume":"347","author":"Mertz","year":"2013","journal-title":"BMJ"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1128\/CVI.00673-14","article-title":"Prospective cohort study on the effectiveness of influenza and pneumococcal vaccines in preventing pneumonia development and hospitalization","volume":"22","author":"Song","year":"2015","journal-title":"Clin. Vaccine Immunol."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Tian, J., Zhang, L., Wang, X., Huang, G., Li, Z., Gong, L., and Liu, D. (2025). Clinical features and survival analysis of adult patients with severe lower respiratory tract infection positive for respiratory syncytial virus. BMC Pulm. Med., 25.","DOI":"10.1186\/s12890-025-03660-7"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Per\u010dini\u0107, A., Vuleti\u0107, T., Lizzul, N., Vuki\u0107 Dugac, A., Gveri\u0107 Grgini\u0107, A., Tabain, I., Juri\u0107, D., and Budimir, A. (2025). Epidemiological and Clinical Characteristics of Adult RSV Infections: A Retrospective Analysis at University Hospital Center Zagreb (2022\u20132024). Pathogens, 14.","DOI":"10.3390\/pathogens14030284"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1069","DOI":"10.1093\/cid\/cit471","article-title":"High morbidity and mortality in adults hospitalized for respiratory syncytial virus infections","volume":"57","author":"Lee","year":"2013","journal-title":"Clin. Infect. Dis."},{"key":"ref_25","first-page":"1","article-title":"Analysis of complex chronic diseases in the elderly: Focusing on outpatient utilization","volume":"196","author":"Jung","year":"2013","journal-title":"Health Welf. Issue Focus."},{"key":"ref_26","unstructured":"Jeong, K.H., Oh, Y.H., Kang, E.N., Kim, K.R., Lee, Y.K., Oh, M.A., Hwang, N.H., Kim, S.J., Lee, S.H., and Lee, S.G. (2017). Survey of the Elderly, Ministry of Health and Welfare, Korea Institute for Health and Social Affairs. Available online: https:\/\/www.mohw.go.kr\/board.es?mid=a10411010200&bid=0019&act=view&list_no=344953."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Presti, S., Manti, S., Gambilonghi, F., Parisi, G.F., Papale, M., and Leonardi, S. (2023). Comparative analysis of pediatric hospitalizations during two consecutive influenza and respiratory virus seasons post-pandemic. Viruses, 15.","DOI":"10.3390\/v15091825"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1002\/ppul.26904","article-title":"Leonardi, Epidemiological shifts in bronchiolitis patterns and impact of COVID-19: A two-season comparative study","volume":"59","author":"Presti","year":"2024","journal-title":"Pediatr. Pulmonol."}],"container-title":["Pathogens"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-0817\/14\/6\/543\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:42:54Z","timestamp":1760031774000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-0817\/14\/6\/543"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,5,29]]},"references-count":28,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2025,6]]}},"alternative-id":["pathogens14060543"],"URL":"https:\/\/doi.org\/10.3390\/pathogens14060543","relation":{},"ISSN":["2076-0817"],"issn-type":[{"value":"2076-0817","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,5,29]]}}}