Pediatric adenovirus infections: 10-year clinical spectrum and predictors of severe disease with emphasis on comorbidities and coinfections.

Human adenoviruses (HAdVs) may cause and are responsible for a broad range of pediatric illnesses. Although several cases are self-limiting, certain children may develop complications requiring pediatric intensive care (PICU). To address the role of HAdVs in children, we aimed to characterize the 10-year clinical spectrum of pediatric HAdVs infections and to identify factors associated with hospitalization and severe disease. This retrospective observational cohort study analyzed the clinical course of children (< 18 years) with laboratory-confirmed HAdV infection episodes treated at a tertiary pediatric center between 2014 and 2024. Demographic features, comorbidities, laboratory results, respiratory support requirements, PICU, and clinical outcomes were collected. The severe outcome was defined as a composite endpoint including PICU admission, invasive mechanical ventilation, and/or 30-day mortality. A total of 877 HAdV infection episodes were included, whereas 276 (31.5%) of the patients were hospitalized. Among hospitalized patients, 32.2% required respiratory support, 18.8% required PICU care, and the 30-day mortality was 2.5%. Overall, 104 children (11.9%) developed severe disease. Underlying medical conditions were significantly more frequent among children with severe disease, while those without underlying disease were more common in the non-severe group (69.8% vs. 22.1%; p < 0.001). Viral coinfections were detected in 35.8% of patients but were not associated with increased hospitalization or severity. In multivariable analysis, male sex (OR 2.30, 95% CI 1.23-4.29; p = 0.009), neurologic disease (OR 2.12, 95% CI 1.01-4.42; p = 0.045), cardiac disease (OR 3.27, 95% CI 1.49-7.17; p = 0.003), and hematopoietic stem cell transplantation (HSCT) (OR 4.32, 95% CI 1.36-13.7; p = 0.013) were independently associated with severe outcome.Conclusion: Human adenovirus infection represents a notable clinical burden in children, with a considerable proportion requiring hospitalization and developing severe disease. Underlying neurologic and cardiac diseases, as well as HSCT, were key risk factors for severe outcome, whereas viral coinfections were common but not associated with worse clinical outcome.