The US Food and Drug Administration has approved Merck’s preventive antibody shot, Enflonsia, to protect infants up to one year of age from respiratory syncytial virus (RSV). The single-dose shot can be administered regardless of birth weight and is the first preventive treatment for RSV.
Enflonsia will be priced at $556 per dose. RSV causes seasonal infections like the flu but is a leading cause of pneumonia and death in infants and older adults. A late-stage trial showed comparable safety to Synagis, a monthly injection currently available for infants.
The approval comes as US hospitals see limited supply of antibody treatment Beyfortus during last year’s RSV season. However, production capacity has tripled and manufacturing sites doubled. The CDC recommends two immunization options: an RSV vaccine given to the mother during pregnancy or an RSV antibody given to the baby.
Merck expects Enflonsia shipments to arrive in time for the 2025-2026 RSV season. The company had earlier said the CDC’s Advisory Committee on Immunization Practices was expected to discuss and make recommendations for Enflonia use in infants, but Health Secretary Robert F. Kennedy Jr. has fired all CDC panel members.
Source: https://www.usnews.com/news/top-news/articles/2025-06-09/us-fda-approves-mercks-rsv-antibody-for-infants