Characterization of Circulating HIV-1 Subtypes in the Central African Republic: Implications for Molecular Surveillance and Therapeutic Management

HIV-1 genetic diversity influences disease progression, antiretroviral therapy response, and diagnostic performance. In the Central African Republic (CAR), HIV-1 group M predominates, but detailed data on circulating subtypes and their clinical impact remain limited. This study aimed to characterize HIV-1 subtypes in CAR and assess their association with patients’ immunovirological profiles. A cross-sectional descriptive and analytical study was conducted in 2025 at the National Laboratory of Clinical Biology and Public Health in Bangui. Ninety adult HIV-1–infected patients were included. Viral RNA was extracted from plasma and amplified by RT-PCR targeting the gag p24 region. Subtyping was performed using restriction fragment length polymorphism (RFLP) analysis with HaeIII, MspI, and AluI enzymes. Agarose gel images were optimized using AI (Topaz Gigapixel AI) to enhance band clarity. Clinical and biological data were analyzed using Epi Info software, with univariate analysis and multivariate logistic regression evaluating associations between subtypes and immunovirological parameters. Among the 90 patients (62% women; median age 34 years), the median CD4 count was 312 cells/mm³ and the median viral load was 63,500 copies/mL. Subtype distribution was: CRF02_AG (53.5%), A (17.8%), C (14.4%), and D (14.4%). CRF02_AG showed a tendency toward higher viral load and lower CD4 counts, though these associations were not statistically significant after adjustment. A viral load > 100,000 copies/mL was the only independent predictor of severe immunosuppression (CD4 < 200 cells/mm³; adjusted OR = 3.62; p = 0.019). CRF02_AG predominates among HIV-1–infected patients in CAR, while subtypes A, C, and D co-circulate at lower frequencies. High viral load is the main determinant of severe immunosuppression, regardless of subtype. These findings support continuous molecular surveillance, optimization of treatment strategies, and reinforcement of public health interventions. The combined use of PCR-RFLP and AI-assisted gel imaging offers a reliable and feasible method for subtype monitoring in resource-limited settings.