Evidence of sexual acquisition of hepatitis C virus (HCV) among men who have sex with men (MSM) receiving pre-exposure prophylaxis through a San Francisco clinic has prompted a call for routine monitoring for the virus among PrEP users. In a letter to the editor in Clinical Infectious Diseases, clinicians from Kaiser Permanente San Francisco Medical Center describe new cases of hep C among two men out of 485 HIV-negative MSM receiving PrEP at the clinic between February 2011 and December 2014.

Considering the infections occurred during 304 person-years of follow-up, the hep C incidence rate was 0.7 per 100 person-years. This infection rate is lower than those observed among populations of HIV-positive MSM in published research. But the two cases add evidence to previous findings that the risk of sexual transmission of hep C is likely not reserved to those who are living with HIV. Additionally, however small the risk of hep C may be, its existence adds to the larger dialogue about having sex without a condom while on PrEP (or not on it, for that matter).

One of the men who contracted hep C was a 46-year-old MSM who started taking Truvada (tenofovir/emtricitabine) as PrEP in August 2013. Through July 2014, he was diagnosed with syphilis twice, rectal gonorrhea once and rectal chlamydia once. In June 2014, he reported having condomless receptive intercourse with a man who had a penile piercing. The following month, he said he was the receptive partner during group sex. He said he had not used injection drugs, been tattooed or had a piercing—all of which are major risk factors for contracting hep C. His liver function tests became abnormal in September 2014, at which time he tested positive for hep C.

The other man was a 37-year-old MSM who started PrEP in October 2013. Between then and November 2014, he was diagnosed with rectal chlamydia three times, rectal gonorrhea twice, and syphilis once. He also denied having any of the three major non-sexual risk factors. His liver function test became abnormal in March 2014, when his hep C test came up positive. For two months prior he had been experiencing nausea, weight loss, joint pain and fatigue. He subsequently underwent 12 weeks of interferon treatment and was cured of the virus.

While the Centers for Disease Control and Prevention recommends hep C testing before starting PrEP, the agency does not recommend ongoing testing for the virus.
The authors of the letter to the editor posit that the cases of these two men suggest a need for routine monitoring, as well as counseling about the risk of sexually contracting hep C.

To access the letter, click here.

To read a POZ/AIDSmeds feature on sexual transmission of hep C among HIV-positive MSM, click here.