Wednesday, August 25, 2010

Treatment as Prevention: The microbicidal gel and us

The big news in HIV Prevention from the Vienna AIDS Conference, that a microbicidal gel could reduce HIV infection, has minimal applicability at this point in time to gay male health issues. This study emerges from a new model of HIV control: Treatment as prevention. Prior HIV efforts have utilized psycho-social-behavioral tactics. The treatment as prevention model, however, utilizes pharmacological tactics with aggressive testing and treating of the infected and the use of microbicidal gels and pre-exposure prophylaxis for the uninfected. While previous microbicidal gels contained detergents as the active ingredient and were ineffective, the gel in this study contained an anti-retroviral drug (tenofovir) as the active ingredient which proved to be effective. This study, however, only examined vaginal use. A study on rectal use of the same microbicidal gel with tenofovir will be completed early next year. At present no one knows the optimum dose of the gel, method and timing of administration, or whether tenofovir should be combined with another antiretroviral. We also don’t know how many people will substitute this gel for condoms, what the risk of that substitution is, or even how to talk about the risk of this substitution. No one has even begun to talk about the cost of this prevention technology. All of this will have to be determined in future trials. It will be years before the gel is available to the public.

Microbicides have the potential to reduce the power gap between the insertive and the receptive partner. The insertive partner can decide whether to use a condom, but the receptive partner (male or female) can apply a microbicidal gel without the insertive partner’s knowledge. This shifting of gendered power can have a major impact on HIV transmission in Africa where women’s unequal power forms a major dynamic of HIV transmission. While this blog addresses gay/bi male issues about microbicides, we have to remember that straight people have anal intercourse as well. At present it is unknown what percentage of infections result from het anal intercourse.

Scientists may have to develop different products, and application schedules for rectal and vaginal use. As HIV transmission occurs more readily in anal sex, a rectal microbicide may require a stronger dose of tenofovir than a vaginal microbicide to achieve the same level of effectiveness. Because of the different physiological functions of the vagina and rectum, the method of application may have to differ as well. In this study the women applied the gel 12 hours before and 12 hours after intercourse. It is not clear if the gel has to remain undisturbed in the vagina or rectum for the 12 hours. If the application must occur a relatively long time prior to and after intercourse and remain undisturbed, not only must the receptive partner (male or female) be able to accurately predict anal intercourse but also bowel movements. Complicating matters further, tenofovir has a know side effect of diarrhea which the women in this study reported. Another proposed application approach would be to insert a ring into the vagina which would distribute the gel on a regular basis. Obviously, this would not be feasible in the rectum. There has been some discussion about abandoning the gel for a tenoforvir prophylactic pill to be taken before sexual activity. All these details will be worked out in future trials but we have to be vigilant that these bottom-specific details are included.

For years now the number of new infections among gay/bi men has been increasing. Obviously, current prevention efforts are not working. We need a diverse and varied set of prevention techniques to meet the erotic and relational diversities among all gay/bi men. This study raises the hopeful possibility that a whole new prevention tool kit may be available.

Chemical prevention, however, allows us to continue to avoid the adult conversations about risk, both relative and acceptable, and the elephant in the back room - sex outside of monogamous relationships. Despite the ubiquity of visual homo-eroticism in general and porn in particular, sex has all but disappeared from gay male public discourse except in terms of HIV prevention, as if disease transmission was the primary reason people had or did not have sex. We need that adult conversation but instead we’ve had a lecture.

All diseases, but HIV in particular, exist in a political and financial context. The development of a rectal specific microbicide will provide numerous opportunities for moralistic posturing and political opportunism. As the gel contains an Anti-RetroViral (ARC), it is not clear if a doctor’s prescription will be required to obtain the gel. According to a New York Times article the gel will cost less that $0.05 per dose to produce if it is produced in China which ignores patents, reducing but not eliminating the cost. While the study shows that tenofovir could have a new use, the prevention of infection, adequate funds do not exist for the tenofovir’s current use, the treatment of the already infected. The proposed use of ARVs for prevention at a time of resource scarcity for the infected threatens to divide the uninfected from the infected. Once again with HIV the benefits of science are mediated by the political power of those affected by HIV and that of our opponents. While any addition to the tool kit of HIV prevention is welcome, the science will be easier than the politics. This HIV prevention technology will only benefit gay male health if we can organize politically to make it benefit us.

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