RESUMEN
Sexually acquired hepatitis C virus (HCV) infections among human immunodeficiency virus (HIV)-uninfected men who have sex with men (MSM) have been rare. With the introduction of preexposure prophylaxis (PrEP) against HIV, we hypothesized that these infections would increase. Between 2013 and 2018, we diagnosed 15 likely sexually acquired HCV infections among 14 MSM using PrEP. Most (87%) were asymptomatic, detected by routine alanine transaminase (ALT) or HCV monitoring. Half reported increasing sex partners and drug use after starting PrEP; 5 reported injection of methamphetamine. Interventions are needed to prevent sexually acquired HCV infections by MSM using PrEP. Centers for Disease Control and Prevention guidelines for monitoring during PrEP should include regular ALT and HCV testing.