<scp>HIV</scp> drug resistance and treatment success in the <scp>Republic of Congo</scp> : Implications for optimized treatment

OBJECTIVES: Increasing rates of HIV-1 drug resistance (HIVDR) threaten the effectiveness of antiretroviral therapy (ART) programmes in sub-Saharan Africa, particularly among children, adolescents and young adults, who face limited treatment options. The Republic of Congo (ROC) lacks comprehensive national data on HIVDR in these vulnerable populations. The study aimed to determine the proportion of virologically unsuppressed young individuals receiving ART in ROC and to characterize the prevalence and patterns of HIVDR. METHODS: A point prevalence analysis was conducted in Pointe-Noire to determine viral load and to characterize resistance-associated mutations (RAMs) in HIV-1 among children, adolescents and young adults receiving ART using next-generation sequencing. Sociodemographic and clinical data were collected to assess associations between resistance, treatment history and adherence. Ethical approval was obtained (Avis n° 034/CIE/FCRM/2021). RESULTS: A total of 510 participants were included, with a median age of 19.5 (IQR 13-40) and a median CD4 T-cell count of 538/μl (IQR 279-901). Among them, 34% (n = 173) had detectable viral loads (> 40 copies/ml) while on ART. Of the viremic cohort, 147 samples were successfully sequenced and showed diverse HIV subtypes, with subtype A1 (21%) being the most prevalent. Drug resistance was most frequently observed against NRTIs and NNRTIs, with M184V (54.1%) and K103N (40.8%) mutations predominating. Resistance to protease inhibitors was rare. Notably, no major resistance was found to integrase inhibitors or capsid inhibitors. CONCLUSIONS: HIV-1 drug resistance is highly prevalent in young people receiving ART in the ROC. This study highlights the urgent need to integrate HIVDR genotyping into clinical practice in the ROC to guide treatment and preserve future treatment options. Strengthened adherence support, resistance testing at treatment failure and equitable access to newer antiretroviral drugs are essential to sustain treatment effectiveness and support progress toward the 2030 global HIV targets.