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Background: Antiretroviral (ARV) drugs are used for HIV treatment and prevention. We analyzed ARV drug use and HIV drug resistance in a cohort of young women in rural South Africa enrolled in the HIV Prevention Trials Network (HPTN) 068 study, which evaluated the use of a cash transfer conditional on school attendance to reduce HIV incidence., Methods: ARV drug testing was performed using plasma samples from 2526 young women. This included 2526 enrollment samples (80 HIV-infected and 2446 HIV-uninfected) and 162 seroconversion samples (first HIV-positive study visit). Testing was performed using a qualitative assay that detects 20 ARV drugs from 5 drug classes. HIV drug resistance testing was performed with the ViroSeq HIV-1 Genotyping System for samples that had HIV viral loads ≥400 copies per milliliter., Results: At enrollment, ARV drugs were detected in 10 (12.5%) of 80 HIV-infected young women. None of 2446 HIV-uninfected young women had ARV drugs detected at enrollment. ARV drugs were also detected in 16 (9.9%) of 162 seroconverters. At enrollment, 9 (13.4%) of 67 young women with genotyping results had HIV drug resistance; resistance was also detected in 9 (6.9%) of 131 seroconverters with genotyping results., Conclusions: Most of the HIV-infected young women in this cohort from rural South Africa were not taking ARV drugs, suggesting they were unaware of their HIV status or were not in care. HIV drug resistance was detected in young women with both prevalent and new HIV infection.

Background: HIV Prevention Trials Network (HPTN) 067/ADAPT evaluated tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) pre-exposure prophylaxis (PrEP) in women (South Africa) and men who have sex with men (Thailand, US). Participants received once-weekly directly observed therapy (DOT) of TDF/FTC, and were then randomized to daily, time-driven, or event-driven PrEP. This report describes characterization of 12 HIV seroconversion events in this trial., Methods: HIV rapid testing was performed at study sites. Retrospective testing included fourth generation assays, HIV RNA testing, Western blot, an HIV-1/2 discriminatory assay, resistance testing, and antiretroviral drug testing., Results: Six of the 12 seroconverters received TDF/FTC in the DOT phase, but were not randomized (3 were acutely infected at enrollment; 2 were infected during the DOT phase; 1 was not randomized because of pregnancy). One of the 6 randomized participants had acute infection at randomization but was not diagnosed for 3-4 months because HIV rapid tests were nonreactive; continued daily PrEP use was associated with false-negative antibody tests and low HIV RNA levels. The 5 participants infected after randomization included 4 with low adherence to the PrEP regimen, and one who reported a 7-day period without dosing before infection. Three participants had TDF/FTC resistance (M184I, K65R), including 2 who received only 4 once-weekly TDF/FTC doses; most TDF/FTC mutations were detected by next generation sequencing only., Conclusions: In HPTN 067/ADAPT, participants who acquired HIV infection had infrequent PrEP dosing or low/suboptimal adherence. Sensitive assays improved detection of HIV infection and drug resistance. Drug resistance was observed with limited PrEP exposure.