Brief Report: Group Sex and Methamphetamine Use Fuel an Explosive Epidemic of Hepatitis C Among HIV-Infected Men Who Have Sex With Men in Bangkok, Thailand.

Background: Increased rates of hepatitis C virus (HCV) infection among HIV-infected men who have sex with men (MSM) and who deny injecting drugs have been reported in resource-rich settings.

Setting: We measured HCV prevalence and incidence in a predominantly MSM cohort with acute HIV infection in Bangkok, Thailand.

Methods: In 2009-2018, participants with acute HIV infection were enrolled into the SEARCH010/RV254 cohort. HCV antibody was measured at enrollment and at least once annually. Infection was confirmed with HCV RNA. Risk factors for HCV were analyzed by proportional hazards regression, with hazard ratios (HRs) calculated in a multivariable model.

Results: Of 573 participants, 94% were MSM, with a median age of 26 years (range 18-70 years). The prevalence of HCV antibody was 9 of the 573, or 1.6% [95% confidence interval (CI): 0.7% to 3.0%]. In 1883 person-years (PY) of follow-up, 39 incident cases were identified (20.7 per 1000 PY, 95% CI: 15.1 to 28.3). All incident cases were identified from 2014 onward, and incidence rose from a range of 7.5-11.4 per 1000 PY between 2014 and 2016 to 44.8 per 1000 PY in 2018 (P = 0.001). Most cases (97.4%) were MSM and denied injecting drugs (37 of the 39, 94.5%). In multivariate analysis, methamphetamine use [adjusted HR 2.33 (95% CI: 1.13 to 4.8), P = 0.022], group sex [adjusted HR 2.54 (95% CI: 1.26 to 5.12), P = 0.009], and a history of positive Treponema pallidum hemagglutination or rapid plasma reagin [adjusted HR 2.43 (95% CI: 1.22 to 4.85), P = 0.012] were significantly associated with incident HCV.

Conclusion: We report an HCV epidemic among this cohort of HIV-infected Bangkok-based MSM. Access to timely HCV diagnosis and treatment is needed to prevent morbidity and to decrease onward transmission.