Early diagnosis and risk factors of acute hepatitis C in high-risk MSM on preexposure prophylaxis.

Background: A high incidence of acute hepatitis C virus (HCV) (AHCV) infection has been reported among at-risk HIV-negative MSM. The optimal strategy for early diagnosis of AHCV in this population is not clearly defined.

Methods: In the ANRS IPERGAY PrEP trial, among high-risk HIV-negative MSM, HCV serology and serum alanine aminotransferase (ALT) were used for screening at enrollment and during follow-up. Behavioral risk factors were compared at baseline between participants who were diagnosed with AHCV during the study compared with those who did not. In participants with a positive HCV serology, we used stored sera to perform the following tests at diagnosis and on previous visits: HCV-antibodies rapid tests, plasma HCV viral load and HCV antigen immunoassay. We evaluated the sensitivity of each test for AHCV diagnosis.

Results: Among 429 enrolled participants, 14 were diagnosed with AHCV infection, with a median follow-up of 2.1 (interquartile range, 1.5-2.8) years. AHCV incidence was 1.40 per 100 person-years (95% confidence interval, 0.74-2.39). Patients with AHCV reported a significantly higher number of sexual acts and/or partners, and more frequent recreational drug use at baseline. At the prior visit before AHCV diagnosis (median of 2 months earlier), sensitivities of HCV RNA and HCV antigen tests were, respectively, 100 and 89%, whereas none of the patients had a positive serology, and only 25% had elevated ALT.

Conclusion: HCV antigen and RNA tests were positive within a median of 2 months before the detection of antibodies and ALT elevation. These tests could be considered for HCV screening in high-risk MSM.