Health. Bronchiolitis: 6 out of 10 babies received Beyfortus treatment this winter in France
This drug reduces the risk of hospitalization for bronchiolitis by an average of 83% in babies under one year old, according to a large analysis published in May.
The second infant immunization campaign against RSV (respiratory syncytial virus), the main virus responsible for bronchiolitis, was a success: in France, 6 out of 10 babies were immunized during the 2024-25 epidemic season with the preventive treatment Beyfortus, the Sanofi laboratory announced on Wednesday. More than 650,000 doses of this antibody developed by AstraZeneca and marketed by Sanofi were delivered in France and six million worldwide during this period, generally running from October to February, the French pharmaceutical group summarized during a press briefing.
Every year, an outbreak of bronchiolitis affects babies, primarily caused by the respiratory syncytial virus (RSV), which typically circulates from October to February. It is the leading cause of hospitalization for babies under one year old. Beyfortus (nirsevimab) reduced the risk of hospitalization for babies under one year old by an average of 83%, according to a meta-analysis published in May , which included 27 studies conducted in five countries during the 2023-2024 season.
An impact also on ear infections...Beyond bronchiolitis, RSV immunization "could also help reduce the overall burden of acute otitis media," according to a French study by the network of 125 pediatricians (PARI), which monitors around thirty infections, presented at the European Congress of Pediatrics (Espid) last week.
The study found that RSV immunization led to a 23.7% reduction in ear infections among all babies under one year old by the winter of 2024-2025 and a 48% reduction among infants under six months old, the most immunized population, according to data provided by Sanofi. "We rarely hospitalize for ear infections. But it's still the leading cause of antibiotic prescriptions," said Robert Cohen, a pediatric infectious disease specialist who contributed to this first study in the world examining the impact of RSV immunization on ear infections.
...and about asthma?The pharmaceutical giant is also studying potential links between bronchiolitis and the development of asthma. "We're sure that some asthma is linked to RSV infections, but the genetic basis is another discussion," emphasizes Dr. Cohen, noting that the onset of asthma is multifactorial, with some cases being allergic or infectious in origin, or linked to pollution.
Initial data on the possible effects of RSV immunization on asthma will be available in 2026, according to Sanofi.
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