Nirsevimab use may reduce infant hospitalizations due to RSV by 82 percent: Lancet

Nirsevimab use may reduce infant hospitalizations due to respiratory syncytial virus (RSV) by 82 percent, shows real world evidence published in The Lancet. The findings are from the first RSV season after introduction of Nirsevimab as part of the three-year NIRSE-GAL study conducted in Galicia and Spain. Real-world evidence demonstrates if a treatment or immunization is effective in day-to-day practice, as opposed to “efficacy” determined in carefully controlled clinical trials. A favorable safety profile was observed following Beyfortus use, consistent with clinical study results.

The results are in consonance with real-world evidence (RWE) reported from several broad infant immunization programs across the US, Spain and France during the 2023-2024 RSV season, which add to the consistent and high efficacy seen in pivotal clinical studies with Beyfortus. 

In addition to NIRSE-GAL study, evidence of the high impact following Beyfortus’ introduction has been consistently shown in several other real-world studies.

• An interim analysis of 2023-24 surveillance data published in the US Centers for Disease Control and Prevention’s (CDC) Morbidity and Mortality Weekly Report (MMWR) shows a single dose of Beyfortus was 90% effective in preventing hospitalizations due to RSV in babies who were immunized below 8 months of age.

• A recent draft recommendation from Haute Autorité de Santé in France reported, across six hospitals, an effectiveness of 83% against RSV-associated hospitalization in infants who received Beyfortus compared to those with no intervention.

• In Catalonia, Spain, a study pre-printed in The Lancet showed reductions of 87.6% and 90.1% in hospital and ICU admissions for RSV, respectively, among babies born before the start of the RSV season, who were eligible to receive Beyfortus, compared to those with no intervention.

• A pooled analysis of data from three Spanish regions, including Valencia, Murcia, and Valladolid, showed an 84.4% effectiveness in preventing hospitalizations due to RSV in infants under 9 months of age versus infants who received no intervention. The results were published in Eurosurveillance.

• A study from Navarra, Spain published in Vaccines found an effectiveness of 88.7% in preventing hospitalizations among infants immunized at birth with Beyfortus, compared to no intervention.

Nirsevimab is the first immunization designed for all infants for protection against RSV through their first RSV season, including for those born healthy at term or preterm, or with specific health conditions that make them vulnerable to RSV disease. Beyfortus is also designed to protect children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season.As a long-acting antibody provided directly to newborns and infants as a single dose, Beyfortus offers rapid protection to help prevent lower respiratory tract disease caused by RSV without requiring activation of the immune system. Beyfortus administration can be timed to coincide with the RSV season.

Respiratory syncytial virus (RSV) is a highly contagious virus that can lead to serious respiratory illness for infants. Two out of three infants are infected with RSV during their first year of life and almost all children are infected by their second birthday.

Federico Martinon Torres, Head of Pediatrics, Hospital Clínico Universitario Santiago, Spain, and principal investigator of the NIRSE-GAL study “Galicia provides the first population-based real-world evidence of the impact of nirsevimab to prevent RSV disease in infants, showing a reduction by almost 90% in the number of hospitalizations due to this virus when compared with several previous RSV seasons. This achievement is the result of the exemplary pragmatic collaboration among scientists, industry, healthcare providers and policy makers aligned with a carefully planned roll-out of the immunization campaign, and the outstanding response of the Galician parents to this prophylaxis campaign.”

Thomas Triomphe, Executive Vice President, Vaccines, Sanofi, “The scale and speed of impact seen after Beyfortus’ introduction demonstrates the strength of all-infant immunization strategies against RSV in babies. In Galicia, we saw an effectiveness of 82% in reducing RSV hospitalizations following the launch of Beyfortus, with more than 90% of eligible infants immunized. A growing body of evidence from these programs supports policymakers, healthcare providers, and parents who share our collective ambition to safeguard babies from RSV disease.”