Retrospective longitudinal analysis of low-level viremia among HIV-1 infected adults on antiretroviral therapy in Kenya

Background: HIV low-level viremia (LLV) (51-999 copies/mL) can progress to treatment failure and increase potential for drug resistance. We analyzed retrospective longitudinal data from people living with HIV (PLHIV) on antiretroviral therapy (ART) in Kenya to understand LLV prevalence and virologic outcomes. Methods: We calculated rates of virologic suppression (≤50 copies/mL), LLV (51-999 copies/mL), virologic non-suppression (≥1000 copies/mL), and virologic failure (≥2 consecutive virologic non-suppression results) among PLHIV aged 15 years and older who received at least 24 weeks of ART during 2015-2021. We analyzed risk for virologic non-suppression and virologic failure using time-dependent models (each viral load (VL) <1000 copies/mL used to predict the next VL). Findings: Of 793,902 patients with at least one VL, 18.5% had LLV (51-199 cp/mL 11.1%; 200-399 cp/mL 4.0%; and 400-999 cp/mL 3.4%) and 9.2% had virologic non-suppression at initial result. Among all VLs performed, 26.4% were LLV. Among patients with initial LLV, 13.3% and 2.4% progressed to virologic non-suppression and virologic failure, respectively. Compared to virologic suppression (≤50 copies/mL), LLV was associated with increased risk of virologic non-suppression (adjusted relative risk aRR 2.43) and virologic failure (aRR 3.86). Risk of virologic failure increased with LLV range (aRR 2.17 with 51-199 copies/mL, aRR 3.98 with 200-399 copies/mL and aRR 7.99 with 400-999 copies/mL). Compared to patients who never received dolutegravir (DTG), patients who initiated DTG had lower risk of virologic non-suppression (aRR 0.60) and virologic failure (aRR 0.51); similarly, patients who transitioned to DTG had lower risk of virologic non-suppression (aRR 0.58) and virologic failure (aRR 0.35) for the same LLV range. Interpretation: Approximately a quarter of patients experienced LLV and had increased risk of virologic non-suppression and failure. Lowering the threshold to define virologic suppression from <1000 to <50 copies/mL to allow for earlier interventions along with universal uptake of DTG may improve individual and program outcomes and progress towards achieving HIV epidemic control. Funding: No specific funding was received for the analysis. HIV program support was provided by the President's Emergency Plan for AIDS Relief (PEPFAR) through the United States Centers for Disease Control and Prevention (CDC).