Failure of pre-exposure prophylaxis with daily TDF/FTC and the scenario of delayed HIV seroconversion.

Abstract Failure of pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate and emtricitabine occurs uncommonly despite perfect adherence, resulting in breakthrough HIV infection. Delayed seroconversion associated with antiretroviral use may complicate the picture, causing uncertainties in interpreting adherence pattern for establishing the true cause of PrEP failure.