A Phase II, Comparative Study of Seroconversion of Single-Dose and Two-Dose Measles Vaccination in HIV-Infected and HIV-Uninfected Children: A Multicenter Trial of the Pediatric AIDS Clinical Trials Group

Inclusion Criteria Patients must have: * Willing to have and receive results of HIV test * Been born to mothers with HIV infection or history of AIDS-defining condition by CDC criteria. * No history of opportunistic infection. * No known exposure to measles within 14 days prior to study entry. * CD4+ lymphocyte count \>= 750 cells/mm3 or more than 15% at 6 months of age. * Parent or legal guardian available to give written informed consent and be willing to comply with all study requirements. * Childhood immunizations (other than measles) according to current recommendations of the Immunization Practice Advisory Committee and American Academy of Pediatrics. NOTE: * Coenrollment on other therapeutic protocols (except for ACTG 185) is permitted. NOTE: * Patients must be located in a geographical area where measles immunization at 12 months is standard of care. Recommended: * Childhood immunizations other than measles according to current guidelines. Exclusion Criteria Co-existing Condition: Patients with the following symptoms or conditions are excluded: * Intercurrent illness and/or fever for 7 days. * Known sensitivity or allergy to neomycin or eggs. Concurrent Medication: Excluded: * IVIG. * Uninterrupted or anticipated steroid therapy (\>= 2 mg/kg/day) for more than 2 weeks duration. Patients with the prior condition are excluded: * Platelet count \< 50,000/mm3 at any time prior to study entry. Prior Medication: Excluded: * Any IgG preparation within the past 6 months.