{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,27]],"date-time":"2026-05-27T21:33:18Z","timestamp":1779917598157,"version":"3.53.1"},"reference-count":51,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2025,2,6]],"date-time":"2025-02-06T00:00:00Z","timestamp":1738800000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diseases"],"abstract":"<jats:p>Background: The aim of this study was to analyze data on pediatric cases of COVID-19 admitted to a tertiary referral hospital in northwest Greece. Methods: A retrospective analysis was conducted on the most common clinical manifestations and laboratory findings, stratified by age group and SARS-CoV-2 strain. Results: A total of 254 children were hospitalized, with a mean age of 4.5 years. Underlying conditions were present in 10.2% of cases; two children required pediatric intensive care unit (PICU) admission, and one child died. The most common hematological manifestations, in general, were neutropenia (30%) and lymphopenia (23%), whereas the findings varied when the children were stratified by age group. Eight children developed multisystem inflammatory syndrome (MIS-C), with the most common findings being anemia (75%), lymphopenia (50%), and thrombocytopenia (25%). Analysis of the SARS-CoV-2 strains revealed the proportions of the dominant strain over time. Fever was the predominant symptom across all strains, particularly in the Omicron group, which also had a high incidence of gastrointestinal symptoms. The longest hospital admission occurred in children with the Omicron strain, followed by the Wuhan, Alpha, and Delta strains. Conclusions: Fever was the most consistent symptom across all age groups and virus strains. The most common hematological manifestations were neutropenia (30%) and lymphopenia (23%). The Omicron strain was associated with the longest hospital stay.<\/jats:p>","DOI":"10.3390\/diseases13020048","type":"journal-article","created":{"date-parts":[[2025,2,6]],"date-time":"2025-02-06T06:30:29Z","timestamp":1738823429000},"page":"48","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["SARS-CoV-2 Variants and Their Impact on Pediatric COVID-19: Clinical Manifestations and Hematological Profiles"],"prefix":"10.3390","volume":"13","author":[{"given":"Konstantinos Paris","family":"Trempelis","sequence":"first","affiliation":[{"name":"Faculty of Medicine, School of Health Sciences, University of Ioannina, 45500 Ioannina, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1244-375X","authenticated-orcid":false,"given":"Chrysoula","family":"Kosmeri","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, University Hospital of Ioannina, 45500 Ioannina, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Panagiotis","family":"Kalavas","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, School of Health Sciences, University of Ioannina, 45500 Ioannina, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1090-3698","authenticated-orcid":false,"given":"Fani","family":"Ladomenou","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, School of Health Sciences, University of Ioannina, 45500 Ioannina, Greece"},{"name":"Department of Pediatrics, University Hospital of Ioannina, 45500 Ioannina, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0032-9047","authenticated-orcid":false,"given":"Ekaterini","family":"Siomou","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, School of Health Sciences, University of Ioannina, 45500 Ioannina, Greece"},{"name":"Department of Pediatrics, University Hospital of Ioannina, 45500 Ioannina, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0142-6110","authenticated-orcid":false,"given":"Alexandros","family":"Makis","sequence":"additional","affiliation":[{"name":"Faculty of Medicine, School of Health Sciences, University of Ioannina, 45500 Ioannina, Greece"},{"name":"Department of Pediatrics, University Hospital of Ioannina, 45500 Ioannina, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1038\/s41586-020-2008-3","article-title":"A new coronavirus associated with human respiratory disease in China","volume":"579","author":"Wu","year":"2020","journal-title":"Nature"},{"key":"ref_2","first-page":"157","article-title":"WHO Declares COVID-19 a Pandemic","volume":"91","author":"Cucinotta","year":"2020","journal-title":"Acta Biomed."},{"key":"ref_3","unstructured":"WHO (2023). 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