Pre-Exposure Prophylaxis or PrEP

Pre-exposure prophylaxis (PrEP) involves putting HIV negative people on antiretroviral drugs (ARV) with the aim of protecting them from HIV infection. This blog looks at some of the pros and cons of PrEP.

Tuesday, October 4, 2011

Treatment As Prevention? Not By a Long Shot

There's an interview available with Myron Cohen on HIV treatment being a possible key to ending the pandemic. It would certainly be wonderful if existing drug therapies could reduce transmission enough for the pandemic to eventually be eradicated. Recent findings show that HIV positive people taking antiretroviral (ARV) drugs are less likely to transmit HIV to their partner. And there are good arguments for starting ARV treatment early, for the benefit of both the positive and the negative partner.

Frustratingly, the benefit of early treatment is highest for heterosexual couples. But the majority of HIV transmissions in the US are through male to male sex and intravenous drug use. However, the findings suggest that HIV treatment and transmission reduction is making a lot of progress in Western countries.

There is a somewhat different problem in African countries. Only a small percentage of HIV transmission is thought to come from intravenous drug use and men having sex with men, combined. And, according to UNAIDS, almost all HIV transmission is either through heterosexual contact or mother to child transmission.

It is clearly not feasible to put all people thought to be at risk of transmitting HIV on ARVs because the majority of them are not aware of their HIV status. And the stigma associated with HIV stems to a large extent from the view that it is almost always transmitted sexually. It means that every African, at least in high prevalence countries, is thought to be at risk, and mostly because of their sexual behavior.

Still, it would be interesting if UNAIDS were to rethink their attitude towards modes of HIV transmission, especially considering the orthodox view is not the result of any empirical investigations. Big Pharma could make a lot of money by persuading Western governments to use even more aid money to pay for drugs for HIV positive people. Global HIV policy would benefit from clarifying the relative contribution of various modes of transmission, sexual and non-sexual. Big money may work where the goal of reducing stigma, or even of implementing effective HIV prevention programs, hasn't.

The role of non-sexual modes of transmission, such as unsafe healthcare and cosmetic services, really needs to be questioned. Unless it is established how people are becoming infected, most prevention interventions will fail. Treatment may help with prevention, but it is not the same as prevention. It doesn't obviate the need to find ways of preventing HIV, however it happens to be transmitted.


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