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.
Showing posts with label test and treat. Show all posts
Showing posts with label test and treat. Show all posts

Monday, December 6, 2010

The Health of the Poor: a Valuable Commodity for Big Pharma

Roger Tatoud wonders out loud about medicalisation of sex in OpenDemocracy but I would be more worried about medicalisation of health. PrEP operates by putting HIV negative people on antiretroviral (ARV) drugs in the hope that this will reduce their susceptibility to the virus. And 'treatment as prevention' advocates claim that putting HIV positive people on ARVs will ensure that they are less likely to transmit the virus to HIV negative people.

Both processes are part of what some claim is a new paradigm. However, treatment is not prevention. It may play a part in prevention programs but it is not thereby a prevention paradigm. And PrEP is of little use without other prevention measures, such as condom use. In fact, condom use on its own is probably just as effective as condom use in conjunction with PrEP.

I've only managed to see the first page of an article by Vinh-Kim Nguyen and others, entitled 'Remedicalising an epidemic: from HIV treatment as prevention to treatment is prevention'. But they seem to be arguing something along similar lines.

Prevention has long been underfunded and transmission rates are not declining in many countries outside of Africa. As for the African countries with declining transmission rates, it is not really clear why they are declining. Declines in incidence started long before most prevention programs came into existence. This was also long before significant rollout of ARVs.

But a few tens of millions of HIV positive people is not a big enough market for the pharmaceutical industry, they have to put tens, or even hundreds, of millions of people on drugs even though they are not sick.

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Monday, November 22, 2010

Will People Use Condoms With Pre-Exposure Prophylaxis or Microbicides?

A trial of combined condom and diaphragm use found that, although condom use increased during the trial, it returned to pre-trial rates afterwards. A commentator notes "What happens after trials has always remained very much a mystery". This appears to be true, and it's very disturbing.

Trial conditions are very different from non-trial conditions. Strict protocols are observed, at least in theory, so one would expect behavior to be substantially different once the intervention in question moves into the field. Especially when the trials show that the intervention only produced a small or temporary change in behavior. But results may even be a mere artefact.

Results of trials of mass male circumcision, microbicides (such as the tenofovir based gel tested in the CAPRISA trial), pre-exposure prophylaxis, test and treat strategies and other approaches to HIV prevention, which depend on the possibility of influencing sexual behavior, all share the risk of being artefacts.

Ariane van der Straten was involved in the Methods for Improving Reproductive Health in Africa project. This showed that, in many areas, the interventions involving diaphragms and lubricant, in addition to condoms and counselling employed for the control group, resulted in slightly higher rates of HIV transmission. However, the differences were not statistically significant.

Van der Straten points out that "it is a challenge to use concurrent HIV prevention methods, particularly barrier methods". All the technical solutions mentioned above require people to continue using condoms, even after circumcision and/or using microbicides or taking pre-exposure prophylaxis. Does she mean 'it is a challenge' or 'it is probably inadvisable'?

The study emphasised an unmet need for birth control, but this is hardly a surprise.

Van der Straten's concluding remark is particularly related to one of the assumptions about microbicides, though it may apply equally to pre-exposure prophylaxis. That is the claim that they are 'female-controlled'. Van der Straten says "In the past we have been naive, thinking that female-controlled methods could be used independent of men's involvement, but it's difficult to use any of these methods secretly, so there is a need to involve male partners in female-controlled methods so that they support their partners".

The full report is also freely available online.

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