Studies to assess the effectiveness of interventions to prevent HIV infection depend upon robust estimates of Baseline HIV incidence rates. The changing landscape of high-risk populations, as well as the evolution of biomedical pre-exposure prophylaxis (PrEP) interventions, requires a contemporary evaluation of HIV incidence as well as demographic, behavioral and other subject factors which may impact HIV incidence. This is a prospective cohort study to measure HIV-1 seroincidence in a study population of HIV-1 uninfected Chinese men who have sex with men (MSM) and transgender women (TGW) who are at high-risk of HIV infection. Approximately 550 subjects who are male sex at birth and have sex with men shall enter the study, which will allow for a 10% drop out rate to maintain 500 subjects at the conclusion of the cohort. This is a single arm cohort study to determine HIV-1 seroincidence rates in high risk MSM and TGW when combined with a comprehensive prevention package including HIV and safe sex counseling, provision of condoms and water-based lubricant, and sexually transmitted infection (STI) screening and referral for treatment. It will be determined what proportion of high-risk MSM and TGW who are given a comprehensive HIV-1 prevention package will acquire HIV-1 infection.