Core Insights - The FDA approved Merck's Enflonsia to protect infants from respiratory syncytial virus (RSV), competing with Sanofi and AstraZeneca's Beyfortus [1][4] - Merck plans to launch Enflonsia ahead of the RSV season, with orders expected to start in July [2] - The approval provides a new treatment option for RSV, which causes significant mortality and hospitalization among infants [3] Company Developments - Merck aims to ensure availability of Enflonsia in the U.S. before the RSV season to alleviate the burden on families and healthcare systems [4] - Enflonsia is a preventative monoclonal antibody that can be administered to infants regardless of weight, offering dosing convenience [5] - Sanofi is increasing the supply of Beyfortus, which generated €1.7 billion ($1.8 billion) in sales last year [6] Industry Context - Other companies, including Pfizer, GSK, and Moderna, offer RSV vaccines, but these are limited to adults and pregnant women [6] - A meeting of CDC vaccine advisors is scheduled for June 25 to 27 to discuss recommendations for RSV shots and other immunizations [7] - In clinical trials, Enflonsia reduced RSV-related hospitalizations by over 84% and lower respiratory infections requiring medical attention by more than 60% compared to a placebo [8]