BackgroundGlobal efforts in meeting the 90–90–90 targets reveal that 70% of infected people know their HIV status, 77% of these are receiving antiretroviral therapy (ART) and 82% of treated patients have viral suppression. Since launching the 'test and treat' strategy and wider access to drugs that bring down the viral load (VL), evaluating viral suppression would help to identify those requiring interventions and to make progress towards meeting the targets in Cameroon.MethodsA study was conducted from October 2015 to August 2017 amongst adults (≥20 years), adolescents (10–19) and children (0–9) at 12, 24, 36 and ≥48 months on ART, monitored at the Chantal BIYA International Reference Centre for research on HIV/AIDS prevention and management (CIRCB) in Yaoundé, Cameroon. VL was established using Abbott m2000RT-PCR. VS was defined as VL <1000 copies/ml; with p<0,05 considered significant.ResultsA total of 1979 patients (70% female) were enrolled (1825 adults, 112 adolescents, 42 children); 1865 were on first-line (NNRTI-based, duration: 48 [IQR 24–48] months) vs. 114 on second-line (PI/r-based, duration: 48 [IQR 36–48] months); with 19%(368) at Month2, 14%(274) at Month24, 10%(207) at Month36% and 54% (1130) at ≥Month48. Overall, viral suppression was 79.4%, and 64.3% had controlled viral replication (VL <40). On first-line, viral suppression was 79.7% (1487) vs. 72.2%(83) on second-line (p=0,076). By ART duration, viral suppression was 83.4%(Month12), 85.8%(Month24), 74.9%(Month36) and 77.3% (≥Month48); p=0,0011. By age-range, viral suppression was 76.2% in children, 54.5% in adolescents, and 80.9% in adults (p<0,0001). By age and ART-regimen, viral suppression on first vs. second line was: children 76.5% vs. 60%; adolescents 51.7% vs. 65.2%; and adults 81.2% vs. 74.7%.ConclusionAbout 80% of Cameroonian patients might be experiencing viral suppression, with a declining performance at adolescence and by 3 years of ART experience. Thus, meeting the viral suppression target by 2020 requires a closer VL monitoring strategy and an adapted adherence support mechanism for adolescents living with HIV in resource-limited settings sharing similar challenges