The US Food and Drug Administration has approved Merck’s shot, designed to protect infants from the respiratory syncytial virus (RSV), ahead of the upcoming season. The shot, marketed as Enflonsia, will compete with Sanofi’s Beyfortus, a similar treatment in short supply during the 2023 RSV season.
Merck expects orders for Enflonsia to begin in July, with shipments delivered before the virus spreads widely. This new option provides doctors with another way to tackle the virus, which causes thousands of deaths among older Americans and hundreds of deaths among infants each year.
RSV complications are a leading cause of hospitalization among newborns. Merck’s Enflonsia can be administered to infants regardless of weight, potentially offering convenience in terms of dosing. AstraZeneca’s Beyfortus has a recommended dosage based on body weight, while Pfizer, GSK, and Moderna also offer RSV vaccines for adults and pregnant women.
The approval is seen as a significant development in the market, which includes several other RSV shots currently available or under development. The companies will await recommendations from outside vaccine advisors to the Centers for Disease Control and Prevention in June, when they will form guidance on RSV shots and other immunizations.
Source: https://www.cnbc.com/2025/06/09/fda-approves-merck-rsv-shot-for-infants-to-rival-sanofi-astrazeneca.html