RSV season is ramping up, and doctors are hoping a new shot to prevent the virus in young children will ease the caseload this year. However, some pediatricians are facing challenges getting supply. The CDC and FDA have approved the Beyfortus antibody shot, from drugmakers AstraZeneca and Sanofi, to prevent respiratory syncytial virus in babies from birth to 8 months old, or in children up to 24 months old with severe risk factors.