The Interrelationship Between Chemsex Engagement and HIV Biomedical Prevention in MSM

HIV biomedical prevention through treatment-as-prevention (TasP) and pre-exposure prophylaxis (PrEP) is highly efficacious for reducing HIV transmission risk. The benefits could be undermined by the rising HIV transmission risks in men who have sex with men (MSM) who engaged in chemsex. This project aims to assess the impacts of chemsex on the growth of the HIV epidemic by exploring the complex relationships between chemsex engagement and usage of HIV biomedical prevention in MSM in Hong Kong. Participants would be recruited from the community and clinics in 2 cross-sectional studies (500 HIV-negative and 500 HIV-positive MSM), for HIV self-testing and completing an electronic questionnaire. The association of chemsex would be examined between PrEP-naïve and PrEP experienced HIV-negative MSM, and between good and poor adherence to antiretroviral therapy (ART) among HIV-positive subjects in case-control analyses using logistic regression and multilevel models. The main outcomes include coverage of biomedical prevention in MSM, and their drug use patterns.