The many benefits of breastfeeding are well documented. However, because of the risk of mother-to-child transmission (MTCT) of HIV from an HIV infected mother to her infant, there is considerable concern over the practice, especially in developing countries. The purpose of this study is to determine the safety and effectiveness of the anti-HIV drug nevirapine (NVP) in preventing MTCT of HIV in breastfeeding infants born to HIV infected women in South Africa, Tanzania, Uganda, and Zimbabwe.
Note: As of 08/10/07, the arm assignments for current and new participants have changed. Please see the above description for this trial for more information. Inclusion Criteria for Mothers: * 18 years of age or older * HIV infected * In third trimester of pregnancy, or at most 3 days post-delivery * If baby is not yet born, planning to deliver at a facility where the study is being conducted * Plan to breastfeed Exclusion Criteria for Mothers: * Complications with this pregnancy * Serious medical condition that would interfere with the study (e.g., that would prevent breastfeeding or adherence to the follow-up schedule), as judged by the on-site clinician Inclusion Criteria for Infants: * Born to an HIV infected mother who is eligible for the study * Weighed at least 2000 grams (4.4 lbs) at birth * Blood sample obtained from the infant for HIV-1 DNA PCR, CBC with differential, and ALT * Infants in a multiple birth are eligible only if both/all infants are eligible for the study and assigned to the same study group * Able to breastfeed (e.g., mother and infant alive with no condition apparent that would prevent breastfeeding) Exclusion Criteria for Infants: * HIV DNA PCR positive at birth * ALT of Grade 2 or higher at birth * Hemoglobin, absolute neutrophil count, or platelet count of Grade 3 or higher at birth * Skin rash of Grade 2B (urticaria), Grade 3, or above * Confirmed or suspected clinical hepatitis * Serious illness or condition that would interfere with compliance with study procedures