Efficacy, Acceptability and Safety of Event-driven HIV PrEP Using TAF/FTC in MSM in Thailand and France.

Inclusion Criteria: * Male at birth age ≥ 18 years old * Reporting having sex with men * Negative 4th generation HIV-1 and HIV-2 test * Reporting condomless anal sex with men not more often than two days during the previous month and able to plan their sexual activity * Risk of HIV acquisition based on self-report of at least one of the following behaviors during the 6 months before enrollment: condomless anal sex with at least 2 different sexual partners, sexually transmitted infection (rectal chlamydia and/or rectal gonorrhea and/or syphilis), provided or received money goods or favor in exchange of sex, binge drinking or use of non-injectable recreational drugs. * Consenting to participate and agreeing to follow the clinical trial procedures, including adherence to study visits every 3 months * In France: Person affiliated with or benefiting from a social security system (article L1121-11of the public health code in France) * May be either PrEP-naïve or PrEP-experienced, but must not have used any long-acting PrEP product in the past 2 years. Non-inclusion criteria: * Symptoms and/or clinical signs consistent with an acute HIV infection * Women and trans women * Taking feminizing hormone therapy * Positive HIV test result at screening or enrollment even if HIV infection is not confirmed * Positive hepatitis B surface antigen test * ALT or AST \> 4 ULN * Estimated glomerular filtration rate \< 60mL/min/1.73m² * History of chronic kidney disease, osteoporosis, osteopenia or pathological fracture not related to trauma * Hypersensitivity to the study products F/TDF or F/TAF * Past or concurrent participation in a HIV vaccine trial or concurrent participation in another clinical trial without the agreement of the principal investigators of the two trials * Use of intravenous drugs within the last 12 months * Person under legal guardianship * Not likely to comply with the clinical trial procedures or with any condition incompatible with study participation, upon the investigator's judgement. * Ongoing Post-Exposure Prophylaxis (PEP) for HIV