A Canadian man who was adherent to his pre-exposure prophylaxis (PrEP) to prevent HIV recently tested positive for the disease (N Engl J Med 2017;376[5]:501-502).
This report suggested that contracting HIV-1 is possible despite adherence to PrEP if a person is exposed to a virus that is resistant to either one of the components of PrEP: emtricitabine or tenofovir disoproxil fumarate, or both.
David Knox, MD, a clinician at the HIV Primary Care and Family Medicine at Maple Leaf Medical Clinic, in