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The FDA has approved AstraZeneca and Sanofi’s nirsevimab (Beyfortus) for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease (LRTD) in neonates and infants born during or entering their first RSV season, and in children up to 2 years of age who are vulnerable to severe RSV disease. Whereas AstraZeneca’s first-in-class RSV-prophylactic antibody palivizumab (Synagis) is dosed monthly, the extended half-life of nirsevimab enables it to provide protection for at least 5 months, the length of a typical RSV season.