Use of nirsevimab was found to be 89% effective against acute respiratory syncytial virus (RSV) infection and 93% effective against hospitalization among children younger than age 5 in a recent study published in JAMA Pediatrics. The study examined data in 7 academic pediatric medical centers in the United States from 2017 to 2020 and data from the 2023-2024 RSV season. It was only in July 2023—right before the 2023-2024 RSV season—that nirsevimab first became available. A maternal RSV vaccine also became available in August 2023, but uptake of the vaccine in pregnant moms was too low to study its effectiveness for the analysis, according to researchers.Â
Not exactly: Nirsevimab, sold under the brand name Beyfortus, is an injectable monoclonal antibody—not technically a vaccine because it relies on passive immunization, according to FAQs from the American Academy of Pediatrics (AAP). AAP also notes that protection lasts about 5 months, covering the typical RSV season.