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 5, 2010

Some Disturbing Considerations Relating to PrEP Trials

Anyhow, the article notes that “Behavioural messages that encourage abstinence, monogamy and use of condoms have had […] only a limited long-term impact on the spread of HIV in that region.” The article calls for HIV prevention strategies to be made relevant, though they are not talking about making them relevant to the possibility that some HIV is not sexually transmitted.

A popular claim about PrEP (and other technological fixes) is that they can be applied by women and are “under their control”. There may be some truth in this. Yet, oral contraception has long been available without most women choosing to avail of it. Many instead opt for injectable versions, thus putting themselves at higher risk of being infected with HIV and other viruses as a result of unhygienic health practices.

Injectable versions of contraception are very popular with married women and sex workers, though perhaps for different reasons. Married women say they are not willing to risk having their husband interfere if they keep oral contraceptives at home, which they have to take regularly. It remains to be seen whether attitudes towards PrEP gel are any different. Is it really ‘under the control of women’?

The question is pertinent because unsafe health care practices are not under any clients control, whether male or female. People might be able to take precautions but they have to know that such practices could lead to infection and they have to know what they can do to protect themselves. The HIV/AIDS industry, in this instance, doesn’t seem to be interested in the strategy being under the control of those who face the risks.

The CAPRISA 004 trial, despite widely repeated claims, did not establish what risks were reduced among those taking part. Was it just the risk of sexual transmission that was reduced or was it also the risk of non-sexual transmission? The difference is crucial.

The article notes that the trial results were not affected by frequency of sex. But sexual activity was not very high during the trial and it decreased over time, as did use of the Tenofovir gel. However, HIV transmission over the course of the trial was extremely high, even among the intervention group.

It is also noted that “average viral load was not significantly different” between the intervention and control groups. The ‘Test and Treat’ strategy, which was being hyped as much as PrEP two years ago, claims that placing every HIV positive person on antiretroviral drugs will reduce viral load and therefore reduce transmission. But there is now evidence that low viral load may not be so closely related to rates of HIV transmission, something I have recently discussed on my other blog, HIV in Kenya.

The Aegis article warns that the results need to be viewed with caution; this can not be stressed enough. These trials, CAPRISA 004 in particular, seem to take little notice of how HIV might be transmitted among the populations taking part in their research. If HIV is not all transmitted sexually, such trials will continue to produce invalid results and people will continue to be exposed unnecessarily to the risk of infection with HIV and other blood-borne viruses.


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