Evaluating the Safety and Immune Response to a Single Dose of a Respiratory Syncytial Virus (RSV) Vaccine in Infants and Children

Human respiratory syncytial virus (RSV) is a common cause of respiratory illness in infants and children around the world. This study will evaluate the safety and immune response to a RSV vaccine in three groups of participants: healthy children who have already had an RSV infection (RSV seropositive), healthy infants and children who have not already had an RSV infection (RSV seronegative), and healthy younger infants who have not been screened for prior RSV infection.