When might an infant entering the first RSV season need nirsevimab even though the mother was properly vaccinated more than 14 days before delivery?

In rare circumstances, nirsevimab (Beyfortus, Sanofi) may be considered for infants in their first RSV season who were born to RSV-vaccinated mothers. These situations may include:

• infants born to mothers who have health conditions that might prevent an adequate maternal immune response to vaccination (an immunocompromising condition caused by disease or immunosuppressive treatment)
• infants whose mothers have conditions associated with reduced transplacental antibody transfer (such as a mother living with HIV infection)
• infants who might have lost maternal antibodies, such as those who have undergone cardiopulmonary bypass or extracorporeal membrane oxygenation (ECMO)
• infants with substantially increased risk for severe RSV disease (such as hemodynamically significant congenital heart disease or intensive care admission requiring oxygen at hospital discharge).

Infants and children age 8–19 months who are at increased risk for severe RSV disease and are entering their second RSV season are recommended to receive nirsevimab regardless of history of maternal vaccination.