Comparative clinical and epidemiological characteristics of influenza and COVID-19 in hospitalized pediatric patients in Romania during and after the SARS-CoV-2 pandemic.

The COVID-19 pandemic significantly altered the epidemiology of respiratory viral infections in children. This study aimed to compare the clinical and epidemiological characteristics of influenza and COVID-19 infections in hospitalized pediatric patients in Romania during the pandemic. We conducted a retrospective observational study at the Alessandrescu-Rusescu National Institute for Mother and Child Health in Bucharest between January 1, 2020, and November 2025. Pediatric patients (0-18 years) hospitalized with COVID-19 infection or influenza A/B type were included. Demographic data, clinical presentation, comorbidities, complications, and outcomes were analyzed. A total of 234 patients with COVID-19 and 235 patients with influenza type A/B were included. The median age in the COVID-19 group was 13.9 months with a median length of hospitalization of 4 days, while in the influenza group, the median age was 32.6 months, with a median length of stay of 5 days. Influenza virus was associated with higher risks of intensive care unit admission, longer hospitalization (P < 0.001), pneumonia (22.0% vs 6.0%, P < 0.001), and acute respiratory failure (18.3% vs 10.7%, P = 0.025). In contrast to adult populations, influenza infection was associated with a more severe clinical course than COVID-19 in hospitalized pediatric patients, despite the younger age of COVID-19 patients. These findings emphasize the importance of preventive strategies against influenza in children.