A new HIV diagnosis is made in a patient who has been taking tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) or tenofovir alafenamide/emtricitabine (TAF/FTC) as oral pre-exposure prophylaxis (PrEP) since their last negative HIV test result.
Prior use of tenofovir-based PrEP raises the possibility that HIV drug resistance mutations may have emerged, which could reduce the efficacy of a standard initial antiretroviral regimen. Regimen selection in this scenario must account for that risk.