RSV is the most common viral cause of serious acute lower respiratory illness (LRI) in infants and children under 5 years of age around the world. RSV illness can range from mild upper respiratory tract illness (URI) to severe LRI, including bronchiolitis and pneumonia. This study will evaluate the safety and immunogenicity of an RSV vaccine in healthy RSV-naïve children.~At study entry, participants will undergo a medical history review, physical examination, blood collection, and a nasal wash. Participants will be randomly assigned to receive the RSV vaccine or placebo at a 2:1 ratio, to be administered as nose drops. Participants will be actively monitored for 28 days following administration of vaccine or placebo; monitoring will include medical history reviews, clinical assessments, and at some visits, nasal washes. On the days when no study visit is scheduled, study researchers will contact participants' parents or guardians for medical follow-up. At a study visit on Day 56, participants will undergo a medical history review, blood collection, and a nasal wash procedure.~From November through March following each participant's study participation, parents or guardians will report respiratory and/or febrile illnesses on a weekly basis via telephone calls to study researchers. Participants may have additional study visits that may include blood collection and/or nasal wash procedures during this follow-up period.~This protocol is a companion study to CIR 285; a study being conducted by the Center for Immunization Research (CIR, Johns Hopkins, Baltimore), and the Laboratory of Infectious Diseases (NIAID, Bethesda). The protocols have identical primary and secondary objectives; immunization schedules; evaluation assays and schedules; safety monitoring and reporting. The protocols will vary slightly in site selection requirements, eligibility requirements and site monitoring. These are all operational issues modified to account for the IMPAACT sites' operations and infrastructure.
Human respiratory syncytial virus (RSV) is a common cause of respiratory illness in infants and children. This study will evaluate the safety and immune response to an RSV vaccine in healthy RSV-naïve children.