A Phase III Study to Evaluate the Safety, Tolerance, and Efficacy of Early Treatment With Zidovudine (AZT) in Asymptomatic Infants With HIV Infection

Inclusion Criteria Patients must have: * HIV infection. * CD4 count \>= 2000 cells/mm3 AND \>= 30 percent of total lymphocytes. * No signs or symptoms of HIV infection (other than lymphadenopathy, mild hepatomegaly, hypergammaglobulinemia, or splenomegaly, which is permitted). * Consent of parent or guardian. Exclusion Criteria Co-existing Condition: Patients with the following symptoms and conditions are excluded: * Serious acute infection requiring parenteral therapy at time of entry. * One or more serious, proven bacterial infections including any of the following: * septicemia; pneumonia; meningitis; bone or joint infection; or abscess of an internal organ or body cavity (excluding otitis media or superficial skin or mucosal abscesses) that are caused by Haemophilus, Streptococcus (including pneumococcus), or other pyogenic bacteria. * Clinical neurologic/neuropsychologic deficits, or a head circumference less than the fifth percentile. Concurrent Medication: Excluded: * Any agent with known antiretroviral activity. * Acetaminophen, ibuprofen, or aspirin for more than 72 hours continuously. Prior Medication: Excluded: * More than 7 weeks of prior antiretroviral or immunomodulator therapy post-natally. Recommended: * PCP prophylaxis. * Immunizations according to current recommendations.