Background: HIV drug resistance (HIVDR) remains a challenge in achieving viral suppression (VS) as defined by WHO, known as low-level viremia (<1000copies/ml). However, VS entails low-level of viral replication and risks of selecting drug resistance mutations (DRMs) which might subsequently jeopardise the success of antiretroviral therapy (ART). Thus, among patients experiencing VS, we sought to determine the sequencing performance and patterns of DRMs.
Method: A cross-sectional facility-based study was conducted among patients experiencing VS at the Chantal BIYA International Reference Centre (CIRCB) from January 2020 through August 2021. For each participant, sequencing of HIV-1 protease-reverse transcriptase was performed, and sequencing performance evaluated. Successfully generated sequences were analysed using Stanford HIVDBv9.0; p<0.05 was considered statistically significant.
Results: A total of 132 participants were enrolled; median age [IQR]: 43[33-51] years; 69% females. Median duration on ART was 19 [12-34.4] months and the majority (51.2%) was on first-line ART regimens. Overall, 38(28.8% [95% CI:21.4-37.4]) sequences were successfully generated, and the success rate varied significantly according to viremia: 47.2% (25/53) at viremia≥200 copies/ml versus 16.5% (13/79) viremia<200 copies/mL, OR=4.5, p=0.001. Overall rate of HIVDR was 92%(35/38; 95% CI [78-99.4]), with 79.9%-NRTI, 79.4%-NNRTI and 15.3% PI/r-resistance. According to viremia, HIVDR was higher (32.0%) at viremia≥200 copies/ml versus viremia<200 copies/ml (7.7%), p=0.013. By drug-class, M184V (74.3%), K103N (45.7%), and M46I (14.2%) were the most frequent DRMs for NRTI, NNRTI and PI/r respectively. In spite being on VS, 41.1 % (14/38) of participants were on suboptimal ART. Seven different HIV-1 strains were identified, with a prevailing CRF02_AG (64%).
Conclusion: In this RLS with broad HIV genetic diversity, HIVDR testing is clinically relevant in patients with VL≥200copies/ml, supported by about 50% sequencing success rate and 40% of these patients needing treatment optimisations for long term ART success. This calls for revision of current VS threshold applied in RLS.