Clinical manifestations and severity of COVID-19 caused by Omicron among paediatric patients aged 0–17 years in Italy
SARS-CoV-2 Omicron variant evolved into multiple sub-lineages, some showing increased transmissibility and immune evasion. Despite decreased risk of severe disease, paediatric hospitalization rose. However, factors influencing clinical outcomes remain unclear. A total of 458 whole-genome Omicron sequences from patients 0-17 years, diagnosed with SARS-CoV-2 at Bambino Gesù Children's Hospital (January-December 2023) were analysed. Clinical features, disease severity and circulating variants were assessed. Phylogenetic analysis was performed, and logistic regression identified factors associated with hospitalization. Among patients, 249 (54.4%) were male, with median age 0.6 years. Comorbidities were present in 105 (22.9%) patients, mainly immunocompromised (21.0%). Infections were predominantly from XBB (75.0%), JN.1 (12.4%), BA.5 (7.4%) and BA.2 (5.2%) clades. Upper respiratory infections predominated (73.8%), followed by asymptomatic (17.2%) and lower respiratory infections (4.6%), with nine patients having ≥ 1 co-infection. Comorbidities and lower respiratory infections were positively associated with hospitalization, while upper respiratory infections showed a negative association. Given the recent shift to RGN integrin-binding motif in Omicron sub-lineages, leading to altered pathogenesis, its presence was evaluated, revealing a predominance of RGN (N = 378, 84.6%). In conclusion, COVID-19 severity in paediatric patients was primarily driven by comorbidities and co-infections, while milder cases in healthy children may be associated with RGN integrin-binding motif.
Authors
- Andrea Smarrazzo (ORCID: https://orcid.org/0000-0001-8947-4429)
- Vanessa Fini (ORCID: https://orcid.org/0000-0002-4489-8137)
- Marta Luisa Ciofi degli Atti (ORCID: https://orcid.org/0000-0001-6492-4497)
- Srinivas Rao Valluri
- Romina Quercia
- Anna Chiara Vittucci (ORCID: https://orcid.org/0000-0002-1164-5563)
- Mustapha M. Mustapha (ORCID: https://orcid.org/0000-0002-4102-2965)
- Cátia Marques (ORCID: https://orcid.org/0000-0001-9151-7360)
- Laura Cursi (ORCID: https://orcid.org/0000-0003-2122-9464)
- Jennifer L. Nguyen (ORCID: https://orcid.org/0000-0002-4064-0227)
- Alberto Villani (ORCID: https://orcid.org/0000-0002-9120-0424)
- Luna Colagrossi (ORCID: https://orcid.org/0000-0001-5618-1523)
- Valeria Fox (ORCID: https://orcid.org/0000-0002-4552-8461)
- Annarita Granaglia
- Matthew D. Mastropaolo (ORCID: https://orcid.org/0000-0002-8148-4742)
- Luciano Pacelli (ORCID: https://orcid.org/0009-0005-9849-0339)
- Carmen D’Amore (ORCID: https://orcid.org/0000-0003-2874-7563)
- Claudia Alteri (ORCID: https://orcid.org/0000-0003-4270-5079)
- Laura Lancella (ORCID: https://orcid.org/0000-0002-1662-4219)
- Rossana Scutari (ORCID: https://orcid.org/0000-0001-8549-9645)
- Cristina Russo (ORCID: https://orcid.org/0000-0001-6178-5460)
- Jingyan Yang (ORCID: https://orcid.org/0000-0001-5523-649X)
- Massimiliano Raponi (ORCID: https://orcid.org/0000-0002-7757-6978)
- Lorena Forquè Rodriguez
- Carlo Federico Perno (ORCID: https://orcid.org/0000-0002-0825-5388)
- Antonella De Santis
- Alessandra Pagliaro
- John M. McLaughlin
- Andrea Campana
Institutions
- Pfizer (United States) (US)
- University of Milan (IT)
- Bambino Gesù Children's Hospital (IT)
- Istituti di Ricovero e Cura a Carattere Scientifico (IT)
Publication Details
- Journal
- Scientific Reports
- Published
- 2025-10-21
- DOI
- https://doi.org/10.1038/s41598-025-20483-y
- Citations
- 1
- Primary Topic
- SARS-CoV-2 and COVID-19 Research
- Type
- article
- Field-Weighted Citation Impact
- 1.40
Funders
- Pfizer
- Ospedale Pediatrico Bambino Gesù
- Ministero della Salute