Vaginal Gel May Prevent HIV
Study Shows Gel Halves Women's HIV Risk
Vaginal Anti-HIV Gel: Confirmation Needed
As welcome as the findings are, the study by the Abdool Karims and colleagues must be confirmed. The study gave the gel to 445 sexually active women in rural and urban South Africa, while 444 women received identical, inactive placebo gel.
Over the course of the study, 38 women who got the gel and 60 women who got the placebo became HIV infected. Overall, that's 39% effectiveness. But women who used the gel in at least 80% of sexual encounters had a 54% prevention rate.
If the gel truly works, however, Salim Abdool Karim believes that women will be much more likely to use it than they were in the study, during which they were warned not to rely on it and that it's safety was unproven.
In terms of safety, the gel did not have negative side effects. Virus in women who became infected with HIV despite gel use was not resistant to Viread.
While the Abdool Karims' study must be confirmed, the findings suggest that they used the right approach. By spiking the gel with a drug that enters cells and repels HIV when it tries to enter them, they took a different tack than previous gels which used general microbicides to kill HIV on vaginal surfaces.
The U.S. National Institute of Allergy and Infectious Diseases (NIAID) already has launched a study to confirm the efficacy of tenofovir gel.
"The NIAID-sponsored VOICE study, which launched last fall and is expected to enroll 5,000 women in four south African countries, will provide additional safety and effectiveness data for a tenofovir-based vaginal gel as an HIV prevention method," NIAID director Anthony Fauci, MD, says in a news release. "The study also will offer some insight as to the gel's acceptability as a product used once a day rather than one that is used before and after sexual intercourse."
Anti-HIV Gel Protects Against Genital Herpes, Too
There's an additional benefit to the tenofovir gel. Salim Abdool Karim reported that it also protects against genital herpes infection -- which itself makes a woman more susceptible to HIV infection.
"We also show a 51% reduction in HSV-2 [genital herpes] infection," he said. "Women who have HSV-2 have twice the risk of acquiring HIV. So this would have the benefit of reducing risk of HIV in women who otherwise would have acquired HSV-2 infection."
Abdool Karim said that Gilead has promised him that it will allow South Africa to manufacture tenofovir gel without having to pay any royalties to the company.
The Abdool Karims and colleagues report the findings in the July 20 online journal ScienceExpress.