NIRSEVIMAB was linked to fewer respiratory syncytial virus (RSV) hospitalizations and severe neonatal outcomes than maternal vaccination with the RSV prefusion F protein (RSVpreF) vaccination in France.

RSV Hospitalization Risk Was Lower

A population-based cohort study from mainland France compared two recently introduced strategies to prevent severe respiratory syncytial virus in infants: maternal immunization with the RSVpreF vaccine during 32 to 36 weeks’ gestation, and passive infant immunization with nirsevimab before hospital discharge. Investigators used data from the French National Health Data System and included infants born between September 1 and December 31, 2024.

The analysis included 42,560 infants, with 21,280 in each group after 1:1 matching by maternity ward discharge date, sex, gestational age, and region. Mean age at inclusion was 3.7 days, and median follow up was 84 days.

Nirsevimab Reduced Severe RSV Outcomes

Across the cohort, 481 hospitalizations for RSV associated lower respiratory tract infection were recorded. Of these, 212 occurred in the nirsevimab group versus 269 in the maternal RSVpreF vaccine group. Compared with maternal vaccination, nirsevimab was associated with a lower risk of RSV related hospitalization, with an adjusted hazard ratio of 0.74.

The benefit extended beyond hospitalization alone. Nirsevimab was also associated with lower risks of pediatric intensive care unit admission, ventilator support, and oxygen therapy. Adjusted hazard ratios were 0.58 for PICU admission, 0.57 for ventilator support, and 0.56 for oxygen therapy.

Findings Add Early Real World Comparison

The authors noted that these findings reflect the first RSV season in mainland France during which both prevention strategies were in use. Results were consistent across subgroup analyses and sensitivity analyses, which supports the robustness of the observed associations.

For clinicians, the study offers an early real world comparison of two major infant RSV prevention approaches. While both strategies are designed to reduce serious RSV disease in early life, passive infant immunization with nirsevimab was associated with lower risks of hospitalization and severe respiratory outcomes in this cohort. The authors emphasized that these findings should be reevaluated in future studies as use of both strategies continues to evolve.

Reference

Jabagi MJ et al. Nirsevimab vs RSVpreF Vaccine for Respiratory Syncytial Virus-Related Hospitalization in Newborns. JAMA. 2026;335(9):787-798.

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