{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T18:28:36Z","timestamp":1788805716698,"version":"build-2803163510"},"reference-count":38,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,8,6]],"date-time":"2025-08-06T00:00:00Z","timestamp":1754438400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>In this paper we aimed to compare seasonality, clinical characteristics, and outcomes of Influenza A and COVID-19 in the context of influenza reemergence and ongoing Omicron circulation. We performed a retrospective comparative analysis at the Teaching Hospital of Infectious Diseases in Cluj-Napoca, Romania. We included adult patients hospitalized with Influenza A or COVID-19 between 1 November 2022 and 31 March 2024. Data were collected on demographics, clinical presentation, complications, and in-hospital mortality. We included 899 COVID-19 and 423 Influenza A patients. The median age was 74 years for COVID-19 and 65 for Influenza A (p &lt; 0.001). The age-adjusted Charlson comorbidity index was higher in COVID-19 patients (5 vs. 3, p &lt; 0.001). Despite this age gap, acute respiratory failure was more common in Influenza A (62.8% vs. 55.7%, p = 0.014), but ventilation rates did not differ significantly. Multivariate models showed Influenza A was associated with increased risk of intensive-care unit (ICU) admission or ventilation, whereas older COVID-19 patients had higher in-hospital mortality (5.67% vs. 3.3%, p = 0.064). Omicron COVID-19 disproportionately affected older patients with comorbidities, contributing to higher in-hospital mortality. However, Influenza A remained a significant driver of respiratory failure and ICU admission, underscoring the importance of preventive measures in high-risk groups.<\/jats:p>","DOI":"10.3390\/microorganisms13081836","type":"journal-article","created":{"date-parts":[[2025,8,6]],"date-time":"2025-08-06T15:09:53Z","timestamp":1754492993000},"page":"1836","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Influenza A vs. COVID-19: A Retrospective Comparison of Hospitalized Patients in a Post-Pandemic Setting"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-8531-3146","authenticated-orcid":false,"given":"Mihai Aronel","family":"Rus","sequence":"first","affiliation":[{"name":"Department of Infectious Diseases, Iuliu Hatieganu University of Medicine and Pharmacy, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4218-8622","authenticated-orcid":false,"given":"Daniel Corneliu","family":"Leucu\u021ba","sequence":"additional","affiliation":[{"name":"Department of Medical Informatics and Biostatistics, Iuliu Hatieganu University of Medicine and Pharmacy, Pasteur Street, No. 6, 400349 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Violeta Tincu\u021ba","family":"Briciu","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Iuliu Hatieganu University of Medicine and Pharmacy, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"},{"name":"Clinical Hospital for Infectious Diseases, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Monica Iuliana","family":"Muntean","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Iuliu Hatieganu University of Medicine and Pharmacy, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"},{"name":"Clinical Hospital for Infectious Diseases, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5703-3415","authenticated-orcid":false,"given":"Vladimir Petru","family":"Filip","sequence":"additional","affiliation":[{"name":"Clinical Hospital for Infectious Diseases, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Raul Florentin","family":"Ungureanu","sequence":"additional","affiliation":[{"name":"Clinical Hospital for Infectious Diseases, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8094-767X","authenticated-orcid":false,"given":"\u0218tefan","family":"Troanc\u0103","sequence":"additional","affiliation":[{"name":"Clinical Hospital for Infectious Diseases, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Denisa","family":"Av\u00e2rvarei","sequence":"additional","affiliation":[{"name":"Clinical Hospital for Infectious Diseases, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4010-2901","authenticated-orcid":false,"given":"Mihaela Sorina","family":"Lup\u0219e","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Iuliu Hatieganu University of Medicine and Pharmacy, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"},{"name":"Clinical Hospital for Infectious Diseases, Iuliu Moldovan Street, No. 23, 400348 Cluj-Napoca, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,8,6]]},"reference":[{"key":"ref_1","unstructured":"ECDC (2024, December 24). 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