This year, pre-exposure prophylaxis (PrEP) advocates noted a stunning disconnect between key organizations that issue guidelines on the use of tenofovir/emtricitabine (TDF/FTC, Truvada) for HIV prevention: The United States Centers for Disease Control and Prevention (CDC) continues to say that people need 20 days of daily TDF/FTC before they can consider themselves protected from vaginal HIV exposure — but the World Health Organization (WHO) has stated that just seven days of the drug is enough. Why the disconnect? How come two respected and influential organizations are providing contradictory information? What should physicians and community health workers tell people with vaginas and their partners about how long they need to take PrEP before it becomes effective?
