Bob Leahy and the myth that because PrEP very occasionally has failed, the reliability of a sustained undetectable viral load as an effective prevention strategy for people living with HIV needs questioning
The HIV world was jumping, if not jittery, last week, with a third case of HIV pre-exposure prophylaxis (PrEP) failure reported, this time, at CROI 2017. Notable was that it did not involve drug-resistance, the cause of the previous two widely reported PrEP failures, including one occurring in Toronto. In fact the reason for PrEP failure in this latest case, a 50-year old gay man from the Netherlands, a heavy drug user who was extremely sexually active – and there may be some clues there – remains a question for scientific debate.
Want to know more? The case is particularly complicated. For a full review of the circumstances go here .
Inevitably the suggestion has been raised on Facebook and elsewhere that PrEP failures point to the unreliability of undetectable viral load as a prevention method. In fact I have heard colleagues who work is gay men’s sexual health tell me that PrEP failures are why you cannot say Undetectable = Untransmittable. a message which even the International AIDS Society and many others, including CATIE, support.
Frankly that’s a fallacious argument that needs to be shot down.
Simply put PrEP and treatment as prevention (TasP®) are two entirely different animals. Comparisons between the differing results of the two make no sense.
One more time . . PrEP is a regime for people who are HIV-negative. Nobody has ever said PrEP is 100% safe – in fact Gilead, the manufacturers of Truvada, recommend it be used in combination with condom use. “Nevertheless PrEP appears to be nearly 100% effective if taken consistently so that there are high drug levels in the body at the time of exposure to HIV” says aidsmap.