Safety of and Immune Response to Recombinant Live Attenuated Parainfluenza Type 3 Virus Vaccine in Healthy Infants and Children

Inclusion Criteria: * Good general health * HPIV3-uninfected * Has received age-appropriate inactivated or subunit routine immunizations at least 2 weeks prior to study entry * Has received age-appropriate live routine immunizations at least 4 weeks prior to study entry and at least 2 weeks for rotavirus and inactivated vaccines * Available for the duration of the trial * Parent or guardian reachable by telephone for post-immunization contact * Parent or guardian willing to provide informed consent Exclusion Criteria: * Known or suspected impairment of immunologic functions. Infants who are HIV-infected, who are bone marrow or solid organ transplant recipients, or who have received immunosuppressive therapy, including systemic corticosteroids within 30 days prior to study entry. Infants who are using topical steroids, topical antibiotic ointments and topical antifungal agents are not excluded. * Major congenital malformations, including congenital cleft palate, cytogenetic abnormalities, or serious chronic disorders * Previously received HPIV3 vaccine * Previous serious vaccine-associated adverse event or anaphylactic reaction * Known hypersensitivity to any vaccine component * Lung or heart disease, including reactive airway disease. Infants with clinically insignificant cardiac abnormalities are not excluded. Infants or children who wheezed once or received bronchodilator therapy once in the first year of life but who have not had any additional wheezing episodes or bron…