Since 2000, hepatitis C virus (HCV) has emerged as a sexually transmitted infection among men who have sex with men (MSM). Although the reported HCV epidemic has largely been confined to HIV infected MSM, spread to HIV negative MSM might have gone unnoticed.
HIV negative MSM at high risk for acquiring HIV who enrolled in the Amsterdam Pre-Exposure Prophylaxis (AMPrEP) project at the Public Health Service of Amsterdam were tested for the presence of HCV antibodies and HCV RNA. If positive for HCV RNA, part of the HCV NS5B gene (709 bp) was sequenced. Maximum likelihood phylogenies (GTR substitution model) were constructed to compare HCV sequences from HIV negative AMPrEP participants, Dutch HIV positive MSM with acute or chronic HCV infection (n=246; period 2000-2015) and Dutch risk groups other than MSM (n=153; period 2000-2015). Bootstrap values >70% define robust phylogenetic clusters.
By June, 2016, all 376 HIV negative MSM had been enrolled in AMPrEP; 18 (4.8%, 95%CI 2.8%-7.5%) were positive for anti-HCV or HCV-RNA at baseline. Of those, 15/18 (83%) had detectable HCV-RNA, including one without detectable anti-HCV. HCV genotyping showed genotype 1a (73%), 4d (20%) and 2b (7%). Of the 15 participants with HCV RNA, 13 (87%) were part of 6 robust MSM-specific HCV clades containing MSM with and without HIV. This included 9/11 HIV negative MSM infected with HCV-1a (Figure 1), and all 4 MSM infected with HCV-4d and HCV-2b. Four out of 17 (24%) HCV positive participants reported injecting drugs in the 3 months preceding PrEP start, compared to 11/354 (3.1%) among HCV negative participants, p-value<0.01.
The HCV prevalence of 4.8% among HIV-negative MSM eligible for PrEP was higher than the prevalence around 1% previously observed among Dutch HIV negative MSM attending an STI clinic and not on PrEP. HCV-mono-infected MSM were infected with the same MSM-specific HCV strains circulating among HCV/HIV co-infected MSM, suggesting spread from HIV positive to high-risk HIV negative MSM. Routine HCV testing should be offered to MSM at high risk for HIV and included in PrEP guidelines.