RESUMEN
INTRODUCTION: Mixed hepatitis C virus (HCV) genotype (GT) infections are clinically important as different genotypes have varied sensitivities to direct-acting antivirals (DAAs). A high prevalence of mixed GT infections was observed in individuals who inject drugs and had multiple HCV exposures. The prevalence of mixed HCV GT infections in men who have sex with men (MSM) and high-risk behaviors was investigated by ultra-deep sequencing (UDS). METHODS: NS5B fragment was sequenced from viruses of patients with recent HCV infection: there were 50 HIV-positive and 18 HIV-negative patients, including 13 from the ANRS Pre-Exposure Prophylaxis (PrEP) IPERGAY study. UDS data were analysed using Geneious (version 10.3.2). Phylogenetic trees were constructed using FastTree (version 2.1). RESULTS: HCV sequencing showed GT1a (47.1%), GT4d (41.2%), GT3a (8.8%) and GT2k (2.9%). We detected three (4.4%) mixed GT infections: one between predominant GT4d and minority GT1a, one between predominant GT4d and minority GT1b, and one between predominant GT1a and minority GT4d virus. The rates of minority GT viral populations detected in viruses of the three patients with mixed GT infections were 0.32%, 10.7%, and 1.3%, respectively. The first two patients were HIV co-infected and the third was HIV-negative under PrEP. The anti-HCV treatment was successful in all three patients. CONCLUSION: This work showed uncommon mixed HCV GT infections in MSM at high risk of multiple HCV exposures. The impact of these infections on treatment response has not been established but further studies on more patients are necessary. To prevent treatment failure in this population, regular monitoring of treatment response is needed, particularly when pan-genotypic treatment is not used.