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Saturday 10 October 2009

PREP HIV prevention - Does it work?

Posted in: HIV
By Craig Young - 18th May 2009

"Does PREP work? "We don't know."
"Pre-Exposure Prophylaxis" (PREP) is the latest buzzword circulating around American HIV- gay male circles to avoid condom use. But does it work? And are unsubstantiated anecdotal remarks endangering real HIV prevention?

PREP is traditionally used by healthcare workers, rape victims or those who have experienced condom mishaps and involves ingestion of traditional HIV drugs like tenofovir, or others used to prevent woman/infant transmission amongst HIV+ pregnant or nursing women.

But does tefonovir actually work as a deterrent to HIV exposure if taken before one has unsafe sex? There is still no formal clinical research that warrants lay and anecdotal optimism amongst those who regularly use PREP instead of condoms. In any case, HIV/AIDS specialists tell us not to abandon condoms, given their proven HIV and STI prevention record, compared to something still unknown.

Even in the United States, PREP use is rare amongst lay HIV- community members, with only about one percent acknowledging that they used it in one sample, although this was compared to sixteen percent of those sampled who'd heard about it. In some worrying cases, there's a worrying tendency amongst the careless to mix P/crystal meth, tenofovir and Viagra in MTV, with nothing known about side-effects or adverse reactions. The tenofovir users obtain their HIV drugs through borrowing them or stealing them off HIV+ friends.

Does PREP work? Again, we don't know. As Steve Weinstein noted in his Advocate article on PREP, there are some important questions to be raised. If it can be eventually shown to do so, are there limits involved to its effectiveness? How often would one have to take it? How long before sex would one have to take it? Do regular PREP users build up tolerance to it, negating its later therapeutic effects if they do turn HIV+ later? Can high HIV+ viral load negate its effects? What about the polydrug angle? And worst of all, does all this anecdotal encourage foster barebacking, as described above?

We don't know. Until we do, again, there is no excuse not to use condoms as a staple of HIV prevention. Assume nothing and go safe.


Steve Weinstein: "The New Condom Conundrum" Advocate 1023 (Feb 2009): 76-79.

Craig Young - 18th May 2009

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