Nirsevimab excels in preventing infant hospitalization for RSV

Compared with maternal vaccination with the RSVpreF (respiratory syncytial virus prefusion F) protein vaccine, infant immunization with nirsevimab is associated with a lower risk of RSV-related hospitalization, researchers report.

The findings appeared on Dec 22, 2025 in JAMA Pediatrics.

“This French national population-based study found that passive immunization with nirsevimab was associated with lower risk of RSV-associated hospitalization during early infancy than maternal RSVpreF vaccination.” the authors said.

As background the authors noted, “Respiratory syncytial virus (RSV) is a leading cause of hospitalization in infants. The comparative effectiveness of 2 recently introduced preventive strategies (infant immunization through placental antibody transfer after maternal vaccination with the RSV prefusion F protein [RSVpreF] vaccine and passive infant immunization with nirsevimab) remains unknown.”

For this new retrospective meta-analysis, the investigators extracted data from the French National Health Data System.

Maternal vaccination with the RSVpreF vaccine took place during 32 to 36 weeks’ gestation of infants born in mainland France between September 1 and December 31, 2024.

Passive infant immunization with nirsevimab took place before hospital discharge.

Infants were matched 1:1 by maternity ward discharge date, sex, gestational age, and region.

Follow-up continued until RSV hospitalization or death, or on February 28, 2025.

The primary outcome was infant hospitalization for RSV-associated lower respiratory tract infection. The secondary outcomes included infant admission to the pediatric intensive care unit (PICU), admission to high-dependency unit, ventilator support, and oxygen therapy.

The investigators evaluated data on 42, 560 infants (mean age at baseline of 3.7 days and 51.7% male), with 21, 280 children in each cohort. The median follow-up was 84 days.

Of 481 hospitalizations for RSV-associated lower respiratory tract infection, 212 (44.1%) occurred in the nirsevimab group vs 269 (55.9%) in the RSVpreF vaccine group (between-group difference, −11.8%).

Compared with the RSVpreF vaccine, passive infant immunization with nirsevimab was associated with a 26% lower risk of hospitalization for RSV-associated lower respiratory tract infection.

Compared with the RSVpreF vaccine, passive infant immunization with nirsevimab was associated with a lower risk of severe outcomes, including PICU admission requiring ventilator support or requiring oxygen therapy.

The results were consistent across subgroups.

The authors concluded, “Compared with maternal vaccination with the RSVpreF vaccine, passive infant immunization with nirsevimab was associated with lower risks of RSV-related hospitalization and severe outcomes. These findings reflect the first RSV season with use of these immunization strategies in mainland France; their use should be reevaluated in future studies.”