Infant RSV vaccination can keep babies out of the hospital, but only for a year

Embargoed until: Publicly released: 2026-08-11 01:00

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Babies vaccinated against RSV are less likely to be hospitalised with the virus during their first RSV season, but this protection likely doesn't last for the following season, according to French research. The researchers studied two cohorts of babies aged 4-5 months across the 2023 and 2024 RSV seasons, matching babies vaccinated with nirsevimab with unvaccinated babies. In 2023, the researchers say 0.8% of the vaccinated cohort and 2.4% of the unvaccinated cohort were hospitalised for RSV, and in 2024 the hospitalisation rate was 0.5% and 1.9% for vaccinated and unvaccinated babies. Following up with these cohorts in the second year after their vaccination, the researchers say there was no difference in hospitalisation rates, suggesting the vaccine's protection only lasts for one season.

News release

From: JAMA

First- and Second-Year Outcomes After Nirsevimab Immunization

This study found that nirsevimab was associated with a substantial reduction in RSV-LRTI–related hospitalizations during the first year across both the 2023-2024 and 2024-2025 seasons. It was not associated with reduced hospitalizations due to non-RSV infections or asthma, nor during the second year of follow-up.

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Journal/
conference: JAMA Pediatrics

Research:Paper

Organisation/s: French National Agency for Medicines and Health Products Safety and French National Health Insurance, France

Funder: None reported

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