At Study Visit 2B, study clinicians will review the viral load result. Participants with a viral load ≤ 1,000 copies/mL will continue their first-line (NNRTI-based) ART regimen without change. Participants with a viral load >1,000 copies/mL will change ART regimen to a second-line, protease inhibitor (PI)-based or, if available, integrase inhibitor (II)-based therapy. Clinicians will also be encouraged to change the nucleos(t)ide reverse transcriptase component of the regimen (for example, changing from zidovudine to tenofovir), based on prior exposures, as well as WHO and national guidelines. All regimen decisions will be made by the study clinician, in cooperation with clinic staff at the study sites. In the case of complex management issues, the site principal investigators (Dr. Bosco Bwana in Mbarara and Dr. Yunus Moosa in Durban) will be contacted to offer input. At the conclusion of Visit 2B-SOC, participants in the SOC arm will be scheduled for a final study visit approximately 6 months later. A final visit at 6 months is chosen to allow ample time for drug suppression for participants with detectable viral load at this 3-month visit. Non-study clinical visits for routine clinical care will continue in the interim as determined and scheduled by clinic staff.