FDA Approves Monoclonal Antibody to Protect Infants from RSV

The World Health Organization has issued its first official recommendations for immunization products to protect infants against respiratory syncytial virus (RSV), a leading cause of severe respiratory infections and hospitalizations in young children globally, especially in low- and middle-income countries. WHO recommends two products: a maternal vaccine administered during the third trimester to transfer antibodies to the baby, and a long-acting monoclonal antibody, nirsevimab, given to newborns for protection during the RSV season. In the United States, the FDA has approved Merck's Enflonsia, a monoclonal antibody that provides protection through a single 105 mg dose during the infant's first RSV season, showing over 60% reduction in medically attended RSV infections and over 84% reduction in hospitalizations. Enflonsia is awaiting recommendation from the CDC’s Advisory Committee on Immunization Practices, with distribution expected before the 2025-2026 RSV season. Studies led by Baylor College of Medicine and Texas Children’s Hospital confirm that these preventive treatments can reduce RSV-related hospitalizations by at least 50% in young infants, the most vulnerable group. Together, these advances represent a significant breakthrough in reducing severe RSV disease and hospital burden in infants worldwide.