Sunday, September 5, 2010

Vaginal Gel is Effective Against HIV

Finally, there’s an HIV prevention method that’s controlled by women. This is especially important for women who are not in a mutually monogamous relationship and who cannot convince their men to use a condom. (In Africa, over 60% of HIV-infected persons are women who contracted the disease via heterosexual sex.)

In a study published last week in Science, nearly 900 sexually active women in a high-risk area in South Africa were supplied with either a vaginal gel containing the antiviral drug tenofovir, or just the gel alone as a control, over a thirty-month period. Women who received the drug were 39% less likely to become infected with HIV, compared to women in the control group.

Why wasn’t the treatment 100% effective? Part of the reason may be that some study participants may not have used the gel properly and consistently. Among women who used the gel as advised (both before and after sex) more than 80% of the time, the reduction in HIV infections was 54%. When the gel was used less than half the time the reduction in infections was only 28%. No one should be surprised; after all condoms, too, only work if you use them!

AIDS researchers are cheering. Although prevention wasn’t perfect, they’ve proved that pre-exposure prophylaxis controlled by women is at least partially effective. The next step will be to find more potent drugs or a more effective delivery method – perhaps a vaginal ring that releases the drug over longer periods of time.

By the way, would you like to know how the researchers monitored compliance to the study protocol (participant’s actual use of the gels)? They counted the used gel applicators returned by the women in the study and compared that number to the 181,340 gel applicators they gave out. Obviously the researchers suspected in advance that compliance might be a problem. You have to admire the researchers’ advance planning and their willingness to do what was necessary to improve the validity of their results.

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