Beyfortus Study Shows 82% Drop in Infant RSV Hospitalizations

Newly published real-world evidence demonstrates that Beyfortus (nirsevimab) significantly reduced hospitalizations due to respiratory syncytial virus (RSV) in infants during the 2023-2024 RSV season. This data, published in The Lancet, highlights an 82% reduction in RSV-related hospitalizations in infants under six months of age who received Beyfortus, compared to those who had no intervention. This finding is part of the ongoing three-year NIRSE-GAL study in Galicia, Spain, conducted in collaboration with the Galician Directorate of Public Health and Sanofi.

The interim results from Galicia align with similar findings from various broad infant immunization programs in the US, Spain, and France. These programs have consistently shown high efficacy and safety of Beyfortus against RSV lower respiratory tract disease, both in controlled clinical trials and in real-world settings. Real-world evidence (RWE) assesses how effective a treatment is in everyday practice, contrasting with the controlled conditions of clinical trials.

Federico Martinon Torres, the Head of Pediatrics at Hospital Clínico Universitario Santiago in Spain and principal investigator of the NIRSE-GAL study, emphasized the significant reduction in RSV hospitalizations, nearly 90%, during the first season post-Beyfortus introduction. He attributed this success to a well-coordinated immunization campaign supported by scientists, healthcare providers, policy makers, and Galician parents.

Thomas Triomphe, Executive Vice President of Vaccines at Sanofi, noted the rapid and effective impact of Beyfortus, with 90% of eligible infants in Galicia immunized and an 82% reduction in RSV hospitalizations observed. This underscores the potential of comprehensive infant immunization strategies against RSV.

NIRSE-GAL's study design is robust, following a large population over three years to evaluate Beyfortus' effectiveness in reducing hospitalizations due to RSV and other lower respiratory tract diseases. The study targets infants born during the RSV season, those under six months at the season's start, and children aged 6-24 months vulnerable to severe RSV disease. The 2023-2024 immunization campaign ran from late September to the end of March.

Additional real-world studies further support Beyfortus' efficacy. In the US, an analysis published by the CDC showed a 90% effectiveness of a single Beyfortus dose in preventing RSV hospitalizations in infants under eight months. In France, a draft recommendation reported an 83% effectiveness against RSV-associated hospitalizations in infants across six hospitals. In Catalonia, Spain, a study showed reductions of 87.6% in hospital and 90.1% in ICU admissions for RSV among eligible babies. A pooled analysis in three Spanish regions found an 84.4% effectiveness, and another study in Navarra, Spain, showed an 88.7% effectiveness in preventing RSV hospitalizations in immunized infants.

Sanofi and AstraZeneca are expanding their manufacturing capacity to meet global demands for Beyfortus, aiming to triple production to ensure sufficient supply for future RSV seasons. With regulatory validations on track, the companies are preparing for large-scale distribution, with the majority of doses available by October.

RSV is a major cause of respiratory illness in infants, leading to significant global hospitalizations and medical costs. Beyfortus, the first immunization designed for all infants, offers protection against RSV through their first season and for vulnerable children up to 24 months. Developed and commercialized by Sanofi and AstraZeneca, Beyfortus has received approvals and special designations from numerous regulatory agencies worldwide.

In summary, the introduction of Beyfortus marks a significant advancement in preventing severe RSV disease in infants, with real-world evidence supporting its high efficacy and safety profile.