Updates on the Clinical Epidemiology of HIV-1 Group O Strains in Cameroon and Potential Implications on Diagnosis and Treatment Strategies

Cameroon is an epicenter of diverse HIV-1 strains, with diagnostic and management challenges. The objective herein was to update HIV-1 non-M prevalence and compare diagnostic performance of two versus three-test algorithms. A facility-based study was conducted in February 2024 on 2207 HIV-1 clinical samples at the Chantal Biya International Reference Centre (Yaoundé, Cameroon). HIV-1 non-M were identified by molecular phylogeny. Rapid diagnostic tests (RDTs) used in the two-test (Determine and KHB colloidal gold) versus three-test (First Response, One Step, and KHB) algorithms were evaluated on non-M, with ACRO (HIV1/2 and p24) as independent RDT. No group N (0%) nor P (0%) was found, whereas nine group O were identified (0.4%; 95% CI, 0.2%—0.8%). For individuals harboring group O (mean age, 43 ± 12 years; 50% female), median (IQR): duration since HIV diagnosis was 627 (423 to 775) weeks; viremia, 12,385 (5340 to 72,682) copies/mL; and CD4 count, 52 (39 to 228) cells/mm³. One Step, KHB, and ACRO detected eight of eight group O (100%); First Response HIV1-2.0, seven of eight (87.5%); and Determine HIV1/2, six of eight (75%), P = 1.00. In this Cameroonian setting, HIV-1 group N and P are scarce, whereas group O remains low (<1%). Transitioning from the two-test (75% performance) to the three-test algorithm (87.5% performance) could lead to improved diagnostic performance on currently circulating HIV-1 group O, calling for updates in RDTs to adapt to viral dynamics.