FEM-PrEP (Truvada®): Study to Assess the Role of Truvada® in Preventing HIV Acquisition in Women

Inclusion Criteria: 1. Willing and able (see criterion 2) to provide written informed consent to be screened for and to participate in the trial 2. Able to answer a percentage of informed consent screening (75%) and enrollment (100%) comprehension quiz questions correctly 3. Between 18-35 years old, inclusive 4. At higher risk of becoming HIV infected 5. Have a final negative result according to the site-specific screening HIV testing algorithm and a final negative result at enrollment according to the study HIV testing algorithm 6. Willing to participate in all aspects of the study and to comply with study procedures, for up to 60 weeks, including: * Be randomized * Use study product as directed * Adhere to follow-up schedule and willing to be contacted by site staff between study visits (by phone and/or in person) * Use a study-approved effective non-barrier method of contraception for the duration of the study * Take study product, as evidenced by swallowing a vitamin tablet that is similar in size to the study product at enrollment * Provide contact information and agrees to some form of contact method throughout the study 7. Not intending to relocate out of the area for the duration of the study participation and does not have a job or other obligations that may require long absences from the area ( \> 1 month at a time) 8. In general good health and have no condition (social or medical) which, in the opinion of the Site Investigator, would make study participation unsafe or complicate data interpretation 9. Not pregnant or breastfeeding, and does not anticipate a desire for pregnancy during the 52 weeks of on-product participation 10. Medically eligible at screening including: * Adequate renal function (serum creatinine ≤ upper limit of normal (ULN) of local range and creatinine clearance ≥ 60ml/min estimated by the Cockcroft-Gault Creatinine Clearance Formula * Adequate hepatic function (hepatic transaminases ALT and AST \< 2x ULN \[according to local normal ranges\]) * HBsAg negative * Serum phosphorus levels above the lower limit of the local normal range (according to local normal ranges - grade 3 \& 4 hypophosphatemia will be excluded even if within normal local ranges) 11. Not received or receiving an experimental HIV vaccine, participating in another HIV prevention study or participating in any other clinical trial with a biomedical intervention 12. No clinical signs of liver disease (e.g., ascites, spider angiomata, hepatomegaly, jaundice) 13. No definite evidence of glycosuria or proteinuria (i.e., no repeated positive \[ ≥ + 1 \] urine dipstick). If a urine dipstick is positive for either glucose and/or protein at the first test, a second urine sample will be tested. 14. No history of pathological bone fractures 15. No history of adverse reaction to latex 16. Not taking any of the following medications: nephrotoxic agents; aminoglycoside antibiotics (including gentamicin); intravenous (IV) amphotericin B; cidofovir; cisplatin; foscarnet; IV pentamidine; oral or IV vancomycin; oral or IV gancyclovir; other agents with significant nephrotoxic potential; drugs that slow renal excretion; probenecid; immune system modulators; systemic chemotherapeutic agents (i.e. cancer treatment medications); systemic corticosteroids; interleukin-2 (IL-2); immunomodulators; interferon (alpha, beta, or gamma); other antiretrovirals (including nucleoside analogs, non-nucleoside reverse transcriptase inhibitors, protease inhibitors or investigational antiretroviral agents)