HIV treatment failure in tertiary care: clinical epidemiology and preliminary mechanistic characterisation

Despite antiretroviral therapy (ART) scale-up in sub-Saharan Africa, treatment failure remains a significant challenge. We characterised virological and immunological outcomes among people living with HIV (PLHIV) attending tertiary care facilities in Nigeria, with exploratory analysis of potential mechanistic factors.

This multi-centre cross-sectional study enrolled 517 HIV-positive adults from four Nigerian tertiary facilities between January 2019 and December 2021. Primary outcomes included viral load suppression (<1,000 copies/mL) and CD4 count. Exploratory mechanistic analyses examined drug resistance mutations (n = 50), immune activation markers (n = 40), and inflammatory biomarkers (n = 35) in pilot subsets.

Among 412 participants with viral load data, only 111 (26.9%; 95% CI 22.7-31.5) achieved viral suppression, substantially below the UNAIDS 95% target. Of 387 with CD4 data, 149 (38.5%; 95% CI 33.6-43.6) had severe immunodeficiency (<200 cells/μL). Among 346 participants with complete data, discordant responses were common: 25.7% showed virological failure with preserved immunity, while 6.6% had immunological failure despite viral suppression. In pilot mechanistic subsets, 86% of viraemic participants harboured drug resistance mutations, with M184V (62%) and K103N (54%) predominating. CD8 T-cell activation (CD38+HLA-DR+) was significantly elevated in viraemic versus suppressed participants (median 28.6% vs. 12.4%; p < 0.001), correlating inversely with CD4 count (ρ = -0.46; p < 0.01).

HIV treatment outcomes at Nigerian tertiary facilities fall substantially short of global targets. The high prevalence of discordant immune-virological responses and preliminary evidence of drug resistance and immune activation suggest multiple interacting pathways to treatment failure. Larger mechanistic studies are warranted to inform targeted interventions.