OBJECTIVES: Respiratory Syncytial Virus (RSV) infection is a major cause of hospitalizations for bronchiolitis in children in France. This study aims to estimate RSV-related hospitalizations in France for infants < 1 year of age and to measure the impact of annual maternal vaccination.

METHODS: A retrospective, real-world study based on the French National hospital database (January 1st, 2015 to December 31st, 2021) was conducted. RSV-related hospitalizations were identified by the presence of one of the following ICD-10 diagnosis codes (J121, J205, J210, J219, J45 and R062). Descriptive statistics on patient characteristics, hospital stays, and associated costs were performed.

To assess the impact of vaccination on the reduction of hospitalization, a Markov model combining the efficacy of maternal vaccination from the MATISSE trial and hospitalizations rates was developed.

RESULTS: Overall, 300 951 hospitalizations and 261 459 patients were identified. Over the study period, 57% of the hospitalizations occurred during the RSV season (November to January) and 43% of stays occurred outside the epidemic seasons. In total, 46% of hospitalizations were identified in infants < 3 months of life and 27% in infants between 3 and 6 months of life. Almost 90% of hospitalizations involved full-term infants. One hospitalization out of 5 required a stay in intensive care unit and 5% required resuscitation support, with higher rate among the youngest patients. Mean hospitalization cost was estimated at 3 100 € for patients < 1 month and 2 207 € for those aged between 1 and 6 months.

By applying the efficacy of maternal vaccination to the RSV-related hospitalizations, a reduction of 57% of hospitalisations was estimated, resulting in a cost saving of 84 million of euros.

CONCLUSIONS: RSV infection represents a considerable burden in hospital setting in France, especially during the first months of life. Maternal vaccination suggests a significant benefit in decreasing this burden.