PrEP in Breastfeeding Study

Inclusion Criteria: For infant's mother and father * Able and willing to provide informed consent for the infant to participate in the study * Of legal age ≥18 years to consent For HIV-uninfected mother, in addition to the criteria noted immediately above: * Willing to provide breast milk samples and breastfeed during the duration of the study 0-24 weeks postpartum * Breastfeeding an infant * HIV-uninfected based on negative HIV rapid tests, both at study screening and at the enrollment visit * Adequate renal function, defined by normal creatinine levels and estimated creatinine clearance ≥60 mL/min * Not infected with hepatitis B virus, as determined by a negative hepatitis B surface antigen test * Not currently using PrEP * Note: single mothers will be eligible to participate in this study. Where possible the father's permission was be obtained. When the father is unknown, incompetent, deceased, or not reasonably available, or when only the mother has the legal responsibility for the care and custody of the child, infant participation will be based on the mother's consent and documentation will be added to file. For infant * Infant born to eligible women (both male and female infants will be included) * Age 0-24 weeks * Otherwise infant has no serious infections or active clinically significant medical problems Exclusion Criteria: * Women breastfeeding more than one child * Preterm babies or infants with low birth weight (i.e. ≤2000mg)