HIV PrEP Priming of Immune Effectors

Inclusion Criteria: * age ≥18 at screening * not intending to move away from the clinic's catchment area for the next 2 years * HIV-1 antibody negative * reports commercial sex work * contact information is provided * written informed consent Exclusion Criteria: * HIV infection at screening * participation in previous or concurrent HIV vaccine trials * lactating, pregnant or planning pregnancy * renal function impairment (serum creatinine \>1.5 mg/dl), Fanconi syndrome * abnormal liver function tests (AST/ALT \> 43 U/L), liver disease, viral hepatitis, hepatitis B virus (HBV) infection * serum phosphorus \<2.2mg/dl, osteoporosis * known sensitivity to components of the Truvada® formulation * any immunosuppressive treatment, such as systemic corticosteroids * assumption of medication that interacts with Truvada® * high likelihood of poor adherence to PREP and clinic attendance * any condition that in the opinion of the attending physician could endanger the health of the participant or render her unsuitable to participate in the trial