Intervention: Tenofovir
Trial phase: Not Applicable
SMILES: C[C@H](Cn1cnc2c(N)ncnc21)OCP(=O)(O)O
Sex: Male
Age groups: Adult | Older Adult
Healthy volunteers: Accepts Healthy Volunteers
Participants at risk: 557
Group description: All study participants will be assigned to this arm and will receive one FTC/TDF tablet orally once a day.

FTC 200 mg/TDF 300 mg fixed-dose combination tablet: Each participant will be directed to take one FTC/TDF tablet orally once a day, with or without food.
Eligibility criteria:
Inclusion Criteria:

Must be either a man who has sex with men or a transgender female
Male sex (at birth)
Willing and able to provide written informed consent
HIV-1 uninfected, defined as having a negative rapid HIV antibody test at both screening visit and enrollment and a negative 4th generation antibody/antigen test at screening
No laboratory evidence of a detectable HIV viral load (San Francisco site only)

Evidence of risk of acquiring HIV-1 infection including any one of the following:

(1) Condomless anal sex with two or more male or transgender female sex partners during the last 12 months; or (2) two or more episodes of anal sex with at least one HIV-positive partner during the last 12 months; or (3) sex with a male or transgender female partner and any of the following STDs diagnosed during the last 12 months or at screening: syphilis, rectal gonorrhea, or rectal chlamydia.

Able to provide a street address of residence or phone number for themselves or two personal contacts who would know their whereabouts during the period of the demonstration project
Adequate renal function: creatinine clearance of 60 ml/min or greater as estimated by the Cockcroft-Gault equation within 45 days of enrollment
A urine dipstick with a negative or trace result for protein within 45 days of enrollment
Fluent in English or in Spanish

Exclusion Criteria:

Signs or symptoms of acute HIV infection
Previously diagnosed active and serious infections including active tuberculosis infection or osteomyelitis and all infections requiring parenteral antibiotic therapy (other than STDs requiring intramuscular injections of antibiotics); active clinically significant medical problems including poorly controlled cardiac disease (e.g., symptoms of ischemia or congestive heart failure) or previously diagnosed malignancy expected to require further treatment
Hepatitis B surface antigen (HBsAg) positive
History of pathological bone fractures not related to trauma
Receiving ongoing therapy with any of the following: investigational antiretroviral agents (PEP is allowed as described in the protocol), interferon (alpha, beta, or gamma) or interleukin (e.g., IL-2) therapy, agents with significant nephrotoxic potential, other agents that may inhibit or compete for elimination via active renal tubular secretion (e.g., probenecid), and/or other investigational agents
Concomitant participation in a clinical trial using investigational agents, including placebo-controlled clinical trials using such agents
At enrollment, has any other condition that, based on the opinion of the investigator or designee, would preclude provision of informed consent; make participation in the project unsafe; complicate interpretation of outcome data; or otherwise interfere with achieving the project objectives