High clustering of acute HCV infections and high rate of associated STIs among Parisian HIV-positive male patients

Background Increasing incidence of hepatitis C virus (HCV) infection in human immunodeficiency virus (HIV)-positive men having sex with men (MSM) has been described in recent years. Phylogenetic analyses of acute HCV infections were undertaken to characterize the dynamics during the epidemic in Paris, and associated sexually transmitted infections (STIs) were evaluated. Methods Sanger sequencing of polymerase gene was performed. Maximum likelihood phylogenies were reconstructed using FastTree 2.1 under a GTR+CAT model. Transmission chains were defined as clades with a branch probability ≥0.80 and intraclade genetic distances <0.02 nucleotide substitutions per sites. STIs detected ≤1 month before HCV diagnosis were considered. Results Among the 85 studied patients, at least 81.2% were MSM. Respectively, 47.6%, 39.0%, 11.0% and 2.4% were infected with genotypes 1a, 4d, 3a and 2k. At least 91.8% were co-infected with HIV. HCV re-infection was evidenced for 24.7% of patients and STIs for 20.0% of patients. Twenty-two transmission chains were identified, including 52 acute hepatitis C (11 pairs and 11 clusters from three to seven patients). Conclusions These results revealed strong clustering of acute HCV infections. Thus, rapid treatment of both chronic and acute infections is needed among this population to decrease the prevalence of HCV, in combination with preventive behavioural interventions.