Success and limitations of the French public health strategy after 2 years of large implementation of respiratory syncytial virus prophylaxis: experience of a tertiary hospital (2018-2025).

Objectives: France has gradually implemented prophylaxis against RSV infections in infants since 2023 and, more recently, in the elderly. This study described the recent evolution of the RSV-hospital burden in a French tertiary hospital.

Methods: Characteristics of patients admitted during the 2023/2024 and 2024/2025 RSV seasons with a RSV-lower respiratory tract infection (LRTI) were compared to those of patients admitted during three preprophylaxis RSV seasons.

Results: Overall, 1114 pediatric inpatients and 41 adults with RSV-LRTI were enrolled, of whom 36% had ≥1 chronic complex condition (CCC). Compared to the preprophylaxis period, the RSV-hospital burden decreased in pediatric units in 2024/2025 (1.4 versus 1.7/1000 inpatients, P = 0.004), as did the proportion of infants aged <6 months among inpatients with RSV-LRTI (27.8% versus 57.7%, P < 0.0001) and that of all subjects requiring admission to intensive care units (17.4% versus 37.7%, P < 0.0001). However, the proportion of inpatients with RSV-LRTI from other age groups did not decrease in recent years. In adult units, the RSV-hospital burden increased in 2024/2025 compared to the preprophylaxis period (0.8 versus 0.4/1000 inpatients, P < 0.0001).

Conclusions: The reduction of the RSV-hospital burden mostly impacted infants <6 months of age. Efforts are needed to reduce the RSV-hospital burden in other age groups, especially in children aged 6-11 months and older individuals with CCC.