A new study published yesterday in the journal Pediatrics, demonstrated that nirsevimab-alip (Beyfortus) injection was highly efficacious in preventing respiratory syncytial virus (RSV)–associated lower respiratory tract disease (LRTD).1
“These results support Beyfortus as a groundbreaking advancement in infant RSV disease prevention. With more than 40 real-world evidence studies to date, this latest study further strengthens the well-established body of data that shows that Beyfortus provides protection against RSV disease to help safeguard the health of all babies, regardless of whether they are born before or during the RSV season,” Ayman Chit, PhD, head of North America Medical, Vaccines, Sanofi, said in a statement.2
The injection met both of its co-primary endpoints. The first endpoint showed babies administered nirsevimab were 87% (CI: 81.7%-91.1%; p<0.0001) less likely to develop RSV disease compared to babies who did not receive the injection. The second co-primary endpoint showed that if a baby who received nirsevimab later tested positive for RSV lung infection there were fewer overall medical visits (adjusted mean difference -0.86, p=0.001) during the illness, including significantly reduced visits to emergency departments and hospitalizations.1
Study Parameters and Other Takeaways
The study was conducted during the 2023-2024 RSV season, and all nirsevimab-eligible, healthy term infants born in April 2023 or later were included. Infants of RSV-vaccinated mothers or with high-risk conditions were excluded from the study and it included 31,900 infants; 15,647 (49.1%) received nirsevimab.1
Overall there were 35 RSV LRTD episodes (6.10/1000 person-years) among nirsevimab-immunized infants vs 462 (58.51/1000 person-years) among nonimmunized infants.1
Additionally, a post hoc analysis of the study evaluated the effectiveness of nirsevimab in preventing RSV hospitalizations among healthy term babies. Using real-world data from a retrospective cohort design, researchers compared hospitalization rates between babies who received nirsevimab and those who did not. The analysis demonstrated a 98% reduction in RSV hospitalizations among babies given the injection compared to those who were not.2
Uptake Challenges
One study found uptake of the injection was a major challenges, despite favorable findings of protection. Moline et al report that during that same 2023-2024 RSV season uptake of the injection remained low, with only 1% of RSV-positive children and 15% of RSV-negative controls receiving nirsevimab during the study period.3
A survey given to pediatricians and obstetrician/gynecologist showed some of the primary challenges to update included parent concerns around the safety and effectiveness of the products, the financial burden of purchasing the products, and reimbursement issues. The survey was conducted in October 2024 and included 200 pediatricians and 200 obstetrician/gynecologists.4
The findings showed that 77.0% of pediatricians offered nirsevimab and 63.0% of OB/GYNs offered respiratory syncytial virus (RSV) vaccine to pregnant women. Providers were confident in the safety and effectiveness of nirsevimab and maternal RSV vaccine.4