A recent study published in The Lancet Infectious Diseases has found that infants immunized with Beyfortus (nirsevimab) during their first respiratory syncytial virus (RSV) season experienced fewer RSV-related hospitalizations in their second season. The NIRSE-GAL study, conducted in Galicia, Spain, is the first real-world population study to examine the impact of a universal Beyfortus immunization program over two consecutive RSV seasons.
The research compared hospitalization rates among infants who received Beyfortus with expected cases based on previous years’ data. Among 12,492 eligible infants, 94.4% were immunized. During the first RSV season, there was an 85.9% reduction in hospitalizations for lower respiratory tract infections related to RSV. In the second season, hospitalizations dropped by 55.3% among those previously immunized as infants.
According to Federico Martinón-Torres, Head of Pediatrics at Santiago University Hospital and principal investigator of the study: “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. These results offer compelling population-based data to inform infant immunization strategies and economic evaluation models.”
Thomas Triomphe, Executive Vice President for Vaccines at Sanofi, stated: “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 noted reductions in primary care consultations for respiratory illnesses during the first season: consultations for acute bronchitis or bronchiolitis declined by nearly one-third; similar decreases were observed for lower respiratory tract infections and for wheezing or asthma symptoms.
Additionally, infants who had been hospitalized due to RSV saw significantly fewer rehospitalizations in their second RSV season after receiving Beyfortus as infants.
RSV is known as a leading cause of hospitalization among all infants worldwide, affecting both healthy and vulnerable populations regardless of whether they are born at term or preterm. Global estimates from 2019 suggest approximately 33 million cases led to over three million hospitalizations among children under five years old.
Beyfortus is designed as a long-acting monoclonal antibody intended to protect all infants through their first RSV season and up to age two if they remain at risk. Since its launch, more than 11 million infants have been immunized with Beyfortus across over 45 countries.
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