Detection and characterization of HIV-1 group O and HIV-2 in the Central African Republic

The Central African Republic (CAR) is characterized by widespread HIV epidemic with notable prevalence and genetic diversity. We herein analysed the genetic diversity of atypical non-M HIV-1 strains. In-house serotyping assays for variants of HIV-1 (M, N, O, P) and HIV-2 were used to test a biological collection of 6092 HIV-seropositive blood samples collected between 2003 and 2014 at the Institut Pasteur de Bangui. Samples indicative of recombinant M/O groups, HIV-2, or those that yield doubtful/negative results underwent further PCR tests and sequencing. We found six atypical HIV strains: specifically, three (0.05%) HIV-1 group O strains (subtype H) detected in samples from 2005, 2008 and 2009, alongside three (0.05%) HIV-2 strains (two group A and one group B) identified in samples from 2007 and 2009. HIV-1/O strains showed a genetic link to Cameroon and Gabon strains. This study highlights the dominance of HIV-1/M in the CAR's HIV epidemic over time and underscores the infrequent occurrence of HIV-1 group O and HIV-2 strains. These findings validate the efficacy of WHO-recommended HIV testing protocols and emphasize the need for adaptive surveillance and management strategies to confront the complexities introduced by the genetic diversity of HIV strains.