Passive Immunization Strategies to Prevent Severe Respiratory Syncytial Virus Infection Among Newborns and Young Infants.

Newborns and young infants are at risk for severe respiratory syncytial virus (RSV) lower respiratory tract infection. Passive immunity is the mainstay of infection prevention in this cohort. Transplacental transfer of maternal antibodies provides the newborn with immediate protection from life-threatening infections, however, is dependent upon gestational age, birth weight, mother's age, recent maternal vaccination, maternal nutritional status, maternal immunocompetence and medical conditions, and placental integrity. Efficient transplacental transfer of RSV-neutralizing antibodies have led to the development and approval of maternal RSV immunization for the protection of the newborn. Additionally, administration of RSV-specific antibodies to infants leads to high serum titers of RSV-neutralizing antibodies and further protection from severe disease.