Findings from a real-world population study from Spain show that universal infant immunization with Beyfortus significantly reduced RSV-related hospitalizations not only in the first RSV season but also into the second year of life.
A universal respiratory syncytial virus (RSV) immunization program using nirsevimab (Beyfortus) was linked to a marked and sustained reduction in RSV-related hospitalizations, according to new data from the NIRSE-GAL study conducted in Galicia. The findings, published in The Lancet Infectious Diseases and presented at the RSVVW’26 conference in Rome, Italy, provide the first prospective, real-world population evidence evaluating a universal nirsevimab program across 2 consecutive RSV seasons.1
The study included nearly all eligible infants in the region, achieving a 94.4% coverage rate (11,796 of 12,492 infants). During the first RSV season, the program was associated with an 85.9% reduction in RSV-related lower respiratory tract infection (LRTI) hospitalizations. Importantly, benefits persisted into the second RSV season, with 55.3% fewer RSV-related hospitalizations among infants who had received nirsevimab during infancy compared with expected rates based on prior seasons.1
By preventing severe RSV infection during the earliest months of life—a critical window for lung development—researchers suggest infants may be less vulnerable to subsequent hospital admissions from RSV or other respiratory infections. “This universal RSV immunization program with Beyfortus showed decreased RSV-related hospitalizations and outpatient illness burden during the first season, with persistent impact seen on RSV hospitalizations through the second season,” Federico Martinón‑Torres, head of pediatrics at Santiago University Hospital and principal investigator of the study, said in a statement. “These results offer compelling population-based data to inform infant immunization strategies and economic evaluation models.”1
Universal infant immunization with nirsevimab was associated with large, real-world reductions in RSV hospitalizations.
Protection extended beyond the first RSV season, suggesting potential long-term respiratory benefits.
Reduced primary care visits and rehospitalizations strengthen the case for population-wide RSV prevention strategies.
Additional benefits were observed beyond hospital settings. During the first RSV season, primary care consultations declined by 30.8% for acute bronchitis or bronchiolitis, 33.4% for lower respiratory tract infections, and 27.7% for wheezing or asthma. Among infants previously hospitalized for RSV, rehospitalizations dropped sharply in the second season, with a 78.2% reduction in RSV-related rehospitalizations and a 62.4% reduction in LRTI.1
“This study builds upon our wealth of evidence supporting the public health value of a Beyfortus immunization program,” Thomas Triomphe, executive vice president of vaccines at Sanofi, said in a statement. “It’s exciting to see the significant impact of this infant immunization program during the first RSV season and truly remarkable to consider a benefit across 2 seasons.”1
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With an extended half-life of 71 days, nirsevimab is a long-acting monoclonal antibody for the prevention of RSV LRTD in infants. Administration is timed to coincide with the RSV season and is provided directly to newborns and infants as a single dose. Nirsevimab offers rapid protection without requiring activation of the immune system.1
