Abstract
BACKGROUND: Rising hepatitis C and B virus (HCV and HBV) rates have been reported in men who have sex with men (MSM) and transgender women (TGW). This study characterizes HCV and HBV infections longitudinally among 2,496 MSM/TGW aged 18-50 years and at risk for HIV acquisition enrolled in an HIV-1 vaccine trial in 18 U.S. cities between 2009-2013. METHODS: Participants completed behavioral surveys, HIV testing, and blood collection over 24 months. Of the 2,397 participants who consented for future testing, 1,792 (74.8%) had available paired stored blood samples at baseline and a later timepoint (Month 24 [N = 999]; if unavailable, M12 [N = 775] or M15 [N = 18]). RESULTS: Among 1,792 participants, 98.1% were MSM, 0.8% were TGW, and the median age was 30 years (IQR 24, 40). Participants reported a median number of 3 male sex partners (IQR 1,5) within the past 3 months. Condomless insertive anal sex was reported by 55.8% and condomless receptive anal sex by 46.7%.1.3% reported injection drug use. During follow-up, 1.4% reported pre-exposure prophylaxis (PrEP) use. At baseline 11/1792 (0.61%) participants had HCV infection (HCV AB positive, RNA detectable), with all having persistent detectable RNA and chronic HCV infection at follow-up. Phylogenetic analysis showed no clusters of HCV infection. 8 participants had HCV AB positive, RNA undetectable at baseline and follow-up, representing past HCV infection with clearance; only 2 acquired HCV, which cleared over 12-24 months. At baseline, 2 participants (2/1792 = 0.11%) had positive HBsAg, indicating chronic HBV infection. Over 12-24 months, 4 (4/1790, 0.22%) developed HBsAg positivity; these participants had HBcAB positivity at baseline, thereby likely representing reactivation. There were no new HBV infections during follow-up. CONCLUSION: Among 1,792 men who have sex with men and transgender women aged 18-50 years and at risk for HIV acquisition enrolled in a U.S. HIV-1 vaccine trial, incident hepatitis C infection rates were extremely low, with no cases of incident hepatitis B infection. These rates of incident HCV infection and HBSAg positivity are lower than previously reported among MSM/TGW.