Among French men who have sex with men (MSM), the epidemic of sexually transmitted hepatitis C virus (HCV) that was once largely restricted to HIV-positive men is now apparently spreading to those who do not have HIV, aidsmap reports.

Publishing their findings in Clinical Infectious Diseases, researchers analyzed data on all reported diagnoses of acute HCV (meaning the virus had been contracted very recently) among MSM between 2014 and 2017 in Lyon, France. The investigators conducted genetic analyses of each man’s hep C to determine whether their infections were closely related to those of others.

Ninety-six MSM were diagnosed with 108 cases of acute HCV during the study period, including 80 men diagnosed for the first time and 28 diagnosed with reinfections following clearance of the virus. Seventy-two of the diagnoses were in HIV-positive men and 24 were in HIV-negative men.

Common risk factors for contracting hep C included injection drug use (reported by men at 33 percent of the diagnoses), snorting drugs (34 percent), group sex (69 percent) and fisting (24 percent). Seventy-nine percent of the HIV-positive men and 96 percent of the HIV negative men reported at least one risk factor for HCV.

Two thirds of the HIV-negative men were taking Truvada (tenofovir disoproxil fumarate/emtricitabine) as pre-exposure prophylaxis (PrEP) when they were diagnosed with HCV.

In 2014, there were 20 acute HCV diagnoses among MSM in Lyon, a rate that doubled to 40 in 2017, at which point 45 percent of the diagnoses were among HIV-negative men.

Among HIV-positive MSM, the HCV diagnosis rate per 100 cumulative years was 1.1 diagnoses in 2014 and 2.4 diagnoses in 2017. The increase in this demographic’s diagnosis rate was only statistically significant (meaning it was unlikely to have been driven by chance) for reinfections. During the study period, the rate of first HCV diagnoses per 100 cumulative years among HIV-positive MSM increased from 1.1 diagnoses to 1.5 diagnoses, a difference that was not statistically significant. Meanwhile, among those HIV-positive MSM who had cleared HCV, the reinfection rate increased from 4.8 diagnoses to 11.8 diagnoses per 100 cumulative years.

Among HIV-negative MSM, the rate of first HCV infections per 100 cumulative years increased 10-fold during the study period, from 0.3 diagnoses in 2014 to 3.0 diagnoses in 2017.

Eight percent of the HCV infections spontaneously cleared without treatment. In 94 cases, the men started direct-acting antiviral (DAA) treatment for the virus, an average of five months after the estimated date of infection.

Ninety-six percent of the infections were genetically related to at least two other infections, meaning they were part of an infection cluster. All told, the infections belonged to eight distinct clusters, each of which included three to 27 infections. Each cluster included at least one person with HIV, and five included at least one HIV-negative individual.

Six of the clusters included someone who had contracted HCV prior to 2014. However, the researchers concluded that by the end of the study period, it was largely men recently infected with HCV who were transmitting the virus. 

High proportions of the members of the largest clusters reported drug use as well as fisting. Evidence suggested that HCV was transmitting among men who shared multiple risk factors, including one cluster of six men diagnosed during the summer of 2017 who reported nasal drug use and had been recently diagnosed with a bacterial sexually transmitted infection. The researchers theorized that all these men may have contracted HCV at a single event.

The study authors concluded that among MSM in Lyon, HCV is spreading from the HIV-positive population to those without the virus through shared high-risk activities, including the use of drugs during sex (known as chemsex in Europe) as well as traumatic sexual practices, such as fisting. The investigators recommend that MSM who engage in such high-risk practices undergo routine testing for HCV and that those who test positive receive prompt DAA treatment as well as risk reduction counseling.

At the International AIDS Conference in Amsterdam (AIDS 2018), researchers reported similar findings about the transmission of HCV among HIV-positive and HIV-negative MSM in Paris.

Another study about the men in Lyon, presented at the 2019 Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle, estimated that within five months, each man transmitted HCV to 2.35 other MSM.

At the same conference, a different team of researchers reported that HIV-positive MSM in New York City who clear HCV are reinfected with the virus at a high rate.

To read the aidsmap article, click here.

To read the study abstract, click here.

To read the conference abstract, click here.