{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,20]],"date-time":"2026-01-20T20:29:48Z","timestamp":1768940988117,"version":"3.49.0"},"reference-count":28,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2025,12,20]],"date-time":"2025-12-20T00:00:00Z","timestamp":1766188800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Children"],"abstract":"<jats:p>Background: Severe pediatric influenza remains a major clinical burden, yet its phenotype in the post-COVID-19 period has not been fully characterized. The pandemic\u2019s infection-control measures created an \u201cimmunity gap\u201d among children, altering viral epidemiology and severity. This multicenter study from T\u00fcrkiye defines the clinical spectrum and outcomes of influenza cases requiring intensive care, providing one of the first regional datasets after the pandemic. Methods: We retrospectively analyzed 85 children with influenza admitted to five tertiary PICUs in \u0130stanbul between 2024 and 2025. Demographics, clinical features and outcomes were compared across groups. Predictors of sepsis, pediatric ARDS, and mechanical ventilation were identified through multivariate logistic regression. Results: Influenza A + RSV co-infection occurred in 14% and affected significantly younger infants, presenting with more severe respiratory distress, hypoxemia, and bronchiolitis. Influenza B was associated with distinct neurotropic features\u2014encephalopathy and seizures in 48%\u2014and a higher risk of sepsis (OR 3.27, 95% CI 1.02\u201310.53). Hypoxemia, elevated vasoactive\u2013inotropic score, and high PaCO2 independently predicted mechanical ventilation and poor outcomes. Only 2\u20134% of children had received influenza vaccination. Conclusions: This multicenter analysis reveals a post-pandemic surge of severe pediatric influenza characterized by dual respiratory and neurological phenotypes. RSV co-infection drives early respiratory failure in infants, whereas Influenza B carries a disproportionate risk of neuroinflammation and sepsis. The study provides evidence from T\u00fcrkiye that the post-COVID \u201cimmunity gap\u201d and critically low vaccination coverage contribute to increased PICU admissions. Strengthening pediatric influenza immunization and RSV prevention policies is urgently warranted to mitigate these outcomes.<\/jats:p>","DOI":"10.3390\/children13010014","type":"journal-article","created":{"date-parts":[[2025,12,22]],"date-time":"2025-12-22T07:01:33Z","timestamp":1766386893000},"page":"14","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Distinct Clinical Phenotypes of Severe Pediatric Influenza in the Post-COVID-19 Era: Insights from a Multicenter PICU Study in T\u00fcrkiye"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4526-0485","authenticated-orcid":false,"given":"G\u00fcnt\u00fcl\u00fc","family":"\u015e\u0131k","sequence":"first","affiliation":[{"name":"Department of Pediatric Intensive Care, School of Medicine, Istanbul University-Cerrahpa\u015fa, 34320 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5264-3038","authenticated-orcid":false,"given":"Servet","family":"Y\u00fcce","sequence":"additional","affiliation":[{"name":"Department of Public Health, Istanbul Provincial Health Directorate, 34122 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3877-0839","authenticated-orcid":false,"given":"Tu\u011fba","family":"Kanar","sequence":"additional","affiliation":[{"name":"Department of Pediatric Intensive Care, School of Medicine, Istanbul University-Cerrahpa\u015fa, 34320 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8273-2226","authenticated-orcid":false,"given":"Nihal","family":"Ak\u00e7ay","sequence":"additional","affiliation":[{"name":"Department of Pediatric Intensive Care, Kanuni Sultan S\u00fcleyman Training and Research Hospital, University of Health Sciences, 34303 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6111-1789","authenticated-orcid":false,"given":"Demet","family":"Tosun","sequence":"additional","affiliation":[{"name":"Department of Pediatric Intensive Care, Kanuni Sultan S\u00fcleyman Training and Research Hospital, University of Health Sciences, 34303 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5541-2171","authenticated-orcid":false,"given":"\u00d6zge","family":"Umur","sequence":"additional","affiliation":[{"name":"Department of Pediatric Intensive Care, Ac\u0131badem Mehmet Ali Ayd\u0131nlar University, 34638 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7892-2927","authenticated-orcid":false,"given":"Muhterem","family":"Duyu","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Division of Pediatric Intensive Care, Istanbul Medeniyet University Prof. Dr. S\u00fcleyman Yal\u00e7\u0131n City Hospital, 34722 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0973-8098","authenticated-orcid":false,"given":"Ay\u015fe","family":"A\u015f\u0131k","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Division of Pediatric Intensive Care, Istanbul Medeniyet University Prof. Dr. S\u00fcleyman Yal\u00e7\u0131n City Hospital, 34722 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8947-420X","authenticated-orcid":false,"given":"Abdulrahman","family":"\u00d6zel","sequence":"additional","affiliation":[{"name":"Department of Pediatric Intensive Care, Ba\u011fc\u0131lar Training and Research Hospital, University of Health Sciences, 34303 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5108-3913","authenticated-orcid":false,"given":"Agop","family":"\u00c7\u0131tak","sequence":"additional","affiliation":[{"name":"Department of Pediatric Intensive Care, Ac\u0131badem Mehmet Ali Ayd\u0131nlar University, 34638 Istanbul, T\u00fcrkiye"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Wolff, T., and Veit, M. 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Open"}],"container-title":["Children"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2227-9067\/13\/1\/14\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,22]],"date-time":"2025-12-22T07:26:26Z","timestamp":1766388386000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2227-9067\/13\/1\/14"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,12,20]]},"references-count":28,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,1]]}},"alternative-id":["children13010014"],"URL":"https:\/\/doi.org\/10.3390\/children13010014","relation":{},"ISSN":["2227-9067"],"issn-type":[{"value":"2227-9067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,12,20]]}}}