Incidence of Hepatitis C Virus Infections Among Users of Human Immunodeficiency Virus Pre-exposure Prophylaxis

Abstract

Sexual transmission of hepatitis C virus (HCV) is well documented among human immunodeficiency virus (HIV)-uninfected individuals. The use of HIV pre-exposure prophylaxis (PrEP) may be associated with engagement in activities that facilitate the transmission of sexually transmitted infections (STIs) and possibly HCV among PrEP users. Between 2012 and 2019, the incidence of HCV and bacterial STIs were calculated among HIV-negative indviduals receiving PrEP at the University Health Network HIV Prevention Clinic.Mucosal, anal, and blood samples were taken to test for HIV, syphilis, and anti-HCV antibodies. Among 344 HIV-uninfected patients receiving PrEP, 86% were men having sex with men (MSM). Five individuals were HCV-antibody positive at the time of PrEP initiation. Serologic and virologic follow-up data were available for 109 HCV-negative individuals over 282 patient-years (PY). Two new infections were recorded, yielding an incidence of primary HCV infection of 0.7 per 100 PY. In contrast with HCV, the incidence rates of chlamydia, gonorrhea, and syphilis were 49.2 per 100 PY, 36.3 per 100 PY, and 5.2 per 100 PY, respectively. Both individuals with new HCV diagnoses reported being MSM with a history of unprotected intercourse and 1 individual also reported recreational drug use. Both individuals were asymptomatic at the time of diagnosis and the infections were detected by routine laboratory monitoring. The low incidence of HCV infections despite significantly higher rates of other STIs suggests that sexual transmission of HCV is uncommon in HIV-negative MSM PrEP users in this community. Performing routine risk-based HCV surveillance among PrEP users should be evaluated. The high incidence of STIs in this population indicates a vital role for periodic STI monitoring in those receiving PrEP.