A new study published in The Lancet Infectious Diseases reveals that Beyfortus (nirsevimab) not only protects infants during their first RSV season but also significantly reduces hospitalizations in the second.
The NIRSE-GAL study, conducted in Galicia, Spain, is the first real-world, population-based investigation of a universal RSV immunization program spanning two consecutive seasons. Researchers found that infants immunized with Beyfortus in their first RSV season had 55.3% fewer hospitalizations in the second season, compared with expected rates based on historical data.
During the first season, the program delivered an 85.9% reduction in RSV-related lower respiratory tract infection (LRTI) hospitalizations among infants, thanks to a 94.4% coverage rate (11,796 of 12,492 eligible infants). By shielding infants during the critical early months of lung development, the vaccine appears to lower the risk of severe RSV and other infections later on.
“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,” said Federico Martinón-Torres, Head of Pediatrics at Santiago University Hospital in Spain and principal investigator of the study.
“These results offer compelling population-based data to inform infant immunization strategies and economic evaluation models.”
Thomas Triomphe, Executive Vice President, Vaccines at Sanofi, added, “This study builds upon our wealth of evidence supporting the public health value of a Beyfortus immunization program. 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 two seasons.”
The study also reported notable reductions in primary care visits during the first RSV season: 30.8% fewer first consultations for acute bronchitis or bronchiolitis; 33.4% fewer consultations for lower respiratory tract infections; 27.7% fewer consultations for wheezing or asthma.
Rehospitalizations among previously RSV-hospitalized infants dropped sharply in the second season, with 78.2% fewer RSV-related rehospitalizations and 62.4% fewer LRTI rehospitalizations. Researchers suggest early protection against RSV may deliver lasting benefits for lung health.
RSV is a highly contagious virus that can cause serious respiratory illness in infants, with most hospitalizations occurring in otherwise healthy full-term babies. Globally, it causes millions of hospitalizations and tens of thousands of deaths in children under five each year.
Beyfortus, the first RSV immunization designed for all infants, provides rapid protection through a single dose timed to the RSV season.
With an extended half-life of 71 days, it offers long-acting defense without requiring immune system activation. Over 11 million infants have received Beyfortus across more than 45 countries, with effectiveness confirmed in more than 50 real-world studies involving 400,000+ infants.
