This proposal extends the Aims of the “parent” R01 to investigate the clinical significance of NVP-resistant HIV-1 in children. The primary goal of this proposal is to determine if a low-cost sensitive assay can predict whether NNRTI-ART will succeed or fail based on testing of blood just prior to beginning treatment. In addition, support of this proposal will further technological training and enhance the expertise of investigators at the Tamilnadu Dr. MGR Medical University (MGR-MU) of Chennai, India, to perform research focused on mother-to-child transmission of HIV-1 (MTCT.)