{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,24]],"date-time":"2026-07-24T18:37:50Z","timestamp":1784918270772,"version":"3.55.0"},"reference-count":29,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,2,26]],"date-time":"2026-02-26T00:00:00Z","timestamp":1772064000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Background\/Objectives: COVID-19 and influenza remain major causes of seasonal hospitalizations, with increasing overlap toward the end of the calendar year. Comparative data from this late-year period remain limited, especially for the Central European region. Methods: We retrospectively analyzed adult patients hospitalized with COVID-19 or influenza between September and December 2025 in nine infectious disease units in Poland. Demographic, clinical, and laboratory characteristics were compared, and independent predictors of in-hospital mortality were identified using multivariable logistic regression. Results: A total of 227 patients with COVID-19 and 87 with influenza were included. COVID-19 hospitalizations predominated in September\u2013October, whereas influenza admissions increased sharply in December. COVID-19 patients were older and more frequently had cancer. Length of hospitalization, baseline oxygen saturation, inflammatory markers, and pneumonia rates were similar between groups. In-hospital mortality was significantly higher among COVID-19 patients (14% vs. 6%). Among patients who died from influenza, none received the latest seasonal vaccine; among patients who died from COVID-19, 84.4% did not receive an updated COVID-19 vaccine. After adjustment, COVID-19 was independently associated with a fourfold increased risk of death, along with hypoxemia and pneumonia. Conclusions: During the last quadrimester of 2025, COVID-19 caused more hospitalizations and higher in-hospital mortality than influenza in Poland. Though other studies have evidenced that COVID-19 severity decreased, it remains to cause a substantial healthcare burden. Our findings also suggest earlier COVID-19 vaccination in Poland (initiated preferentially before September) and enhanced healthcare preparedness during late-year periods of viral co-circulation.<\/jats:p>","DOI":"10.3390\/vaccines14030210","type":"journal-article","created":{"date-parts":[[2026,2,26]],"date-time":"2026-02-26T13:58:03Z","timestamp":1772114283000},"page":"210","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["COVID-19 Versus Influenza Hospitalizations in Late 2025 in Poland: A Multicenter Retrospective Comparison"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4713-0801","authenticated-orcid":false,"given":"Piotr","family":"Rzymski","sequence":"first","affiliation":[{"name":"Department of Environmental Medicine, Poznan University of Medical Sciences, 60-806 Pozna\u0144, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dominik","family":"Sznajder","sequence":"additional","affiliation":[{"name":"Department of Infectious and Tropical Diseases and Acquired Immunodeficiency, Pomeranian Medical University, 70-111 Szczecin, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ma\u0142gorzata","family":"Wajdowicz","sequence":"additional","affiliation":[{"name":"Medical Center in \u0141a\u0144cut, Clinical Department of Infectious Diseases and Hepatologic Unit, University of Rzesz\u00f3w, 35-959 Rzesz\u00f3w, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Moniuszko-Malinowska","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Neuroinfection, Medical University of Bialystok, 15-540 Bia\u0142ystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Monika","family":"Pazgan-Simon","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Wroc\u0142aw Medical University, 50-370 Wroc\u0142aw, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pawe\u0142","family":"Skwara","sequence":"additional","affiliation":[{"name":"Department of Infectious and Tropical Diseases, Jagiellonian University Medical College, 330-688 Krak\u00f3w, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Justyna","family":"Hlebowicz","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Medical University of Bialystok, 15-540 Bia\u0142ystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5678-5669","authenticated-orcid":false,"given":"Katarzyna","family":"Sikorska","sequence":"additional","affiliation":[{"name":"Division of Tropical and Parasitic Diseases, Institute of Maritime and Tropical Medicine, Medical University of Gdansk, 80-210 Gdynia, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maciej","family":"Piasecki","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Medical University of Silesia, 41-500 Katowice, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3394-1635","authenticated-orcid":false,"given":"Robert","family":"Flisiak","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Hepatology, Medical University of Bialystok, 15-540 Bia\u0142ystok, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0938-1084","authenticated-orcid":false,"given":"Dorota","family":"Zar\u0119bska-Michaluk","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases and Allergology, Jan Kochanowski University, 25-317 Kielce, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,26]]},"reference":[{"key":"ref_1","unstructured":"GBD 2021 Upper Respiratory Infections Otitis Media Collaborators (2025). 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