Work

Impact of national RSV immunization programme on the epidemiology of bronchiolitis in Greece

Year: 2026

Type: article

Abstract: Universal RSV immunization strategies for infants, including monoclonal antibody administration and maternal vaccination during pregnancy, were implemented in Greece for the first time during the 2025-2026 season. We conducted a prospective observational study of infants aged <12 months hospitalized with bronchiolitis at a quaternary paediatric hospital in Greece between November 2025 and April 2026. Bronchiolitis incidence was compared with that of the 2023-2024 and 2024-2025 seasons. Severity of bronchiolitis was assessed using the modified Tal score. Across the three seasons, 854 of 15246 admissions were due to bronchiolitis. The incidence decreased significantly in 2025-2026 to 42 per 1000 admissions, compared to 64 and 59 in 2024-2025 and 2023-2024, respectively. The 2025-2026 epidemic curve of bronchiolitis was flatter and more prolonged, with a delayed peak in March. Of 186 infants with bronchiolitis, 19.9% had received RSV immunization. Disease severity and oxygen requirements did not differ significantly between immunized and unimmunized infants, although unimmunized infants were older and had a trend towards higher complication rates. In conclusion, national RSV immunization was associated with reduced bronchiolitis hospitalizations and complications. However, the smaller-than-expected reduction in disease rates underscores the need to improve awareness, coverage, and timely immunization.

Source: Epidemiology and Infection

DOI: 10.1017/s0950268826102362