According to study results published in Clinical Infectious Diseases, the epidemiology of acute hepatitis C virus (HCV) infections in men who have sex with men (MSM) has been changing in recent years in France, spreading from MSM with HIV to MSM without HIV and use of pre-exposure prophylaxis (PrEP), mainly through sharing of high-risk activities such as using illicit drugs to enhance a sexual encounter (chemsex) and traumatic sexual practice (ie, participation in sex parties, and/or fisting).

This study included all MSM diagnosed with acute HCV infections at Lyon University Hospital in France with the main aim of analyzing the risk factors, incidence, and HCV transmission patterns in people with HIV and PrEP-using MSM.

From 2014 to 2017, 108 acute HCV infections (80 first infections and 28 re-infections) were diagnosed in 96 MSM (72 individuals with HIV, 24 individuals who are HIV-negative and use PrEP). Only 67% of people without HIV were receiving PrEP at the time of diagnosis. Individuals without HIV were younger than individuals with HIV and more frequently reported drug use and the practice of fisting.

Risk factors for HCV infection included intravenous drug use (33%), nasal drug use (34%), participating in sex parties (69%), fisting (24%), and any drug or sexual risk behavior (83%). Moreover, HCV risk factors and genotypes did not differ between HCV first infections and re-infections.

In MSM with HIV, the incidence of acute HCV infections rose from 1.1/100 person-years (95% CI, 0.7-1.7) in 2014 to 2.4/100 person-years (95% CI, 1.1-2.6) in 2017. But the increase was only significant for re-infections, with the incidence rate rising from 4.8/100 person-years (95% CI, 1.2-12.5) in 2014 to 11.8/100 person-years (95% CI, 5.7-21.3) in 2017 (P =.05).  

On the other hand, the incidence of a first infection in PrEP-users increased from 0.3/100 person-years (95% CI, 0.06-1.0) in 2016 to 3/100 person-years (95% CI, 2.0-5.5) in 2017 (P =.002). The incidence of acute HCV infections in PrEP-users was not determined before 2016, since PrEP was authorized and reimbursed beginning in January 2016 and re-infection incidence was not determined as a result of a limited number of cases.

Cluster analysis included 89 HCV NS5B or NS5A sequences of the 108 acute HCV infections and 25 sequences from MSM with HIV identified before 2014. All clusters and pairs included strains from MSM with HIV. “At least 50% of the clusters started with MSM who have HIV chronically infected by HCV before 2014, indicating that chronically infected patients represented a significant reservoir fueling the epidemic before 2014,” noted the researchers. “However, the combined analysis of phylogeny and periods of contagiosity suggests that transmission mainly occurred between individuals at the acute stage of HCV infection since 2014,” they continued. Of note, no sequence from the 121 controls from the general population was included in MSM clusters.

A key limitation of the study was the lack of screening for HCV in MSM without HIV not receiving PrEP.

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Systematic and frequent HCV screening in MSM who engage in high-risk practices is essential regardless of HIV status. “[Direct-acting antiviral] treatment and harm-reduction interventions should be offered early following the diagnosis of [acute HCV infections] in this population in order to limit the epidemic spread and avoid re-infections,” concluded the researchers.

Reference

Ramière C, Charre C, Miailhes P, et al; Lyon Acute Hepatitis Study Group. Patterns of HCV transmission in HIV-infected and HIV-negative men having sex with men [published online February 27, 2019]. Clin Infect Dis. doi:10.1093/cid/ciz160