By Gwyneth Dickey, Science News
A new vaginal gel is the first to show promise in preventing HIV infection among women, researchers report. If licensed, the gel could be an effective female-initiated means of HIV prevention, which is especially important in places like Africa where condom use can be difficult for women to negotiate.
“Now we have a product that can potentially alter this and save millions of lives by preventing HIV infection and preventing death,” says infectious diseases epidemiologist Quarraisha Abdool Karim of Columbia University, who coauthored the study being published online July 19 by Science.
In sub-Saharan Africa, women and girls account for about 60 percent of HIV infections. Currently, these victims have no way to protect themselves against HIV if their male partners refuse to use condoms. Researchers have been working for over a decade to create a topical gel that women can use vaginally to prevent infection, but none has proven successful.
The new gel contains an anti-HIV drug called tenofovir. Tenofovir is already used in pill form because it helps slow HIV’s spread through a patient’s body. The secret to tenofovir’s success as a topical agent may be that it absorbs into the vaginal wall and into the cells targeted by HIV, says infectious-disease epidemiologist Salim Abdool Karim, another coauthor on the study. Other gels have had to be sufficiently spread around and present in the vagina during intercourse in order to work, he adds.
Researchers recruited 889 sexually active women between the ages of 18 and 40 in KwaZulu-Natal, South Africa. Half of the women were given the tenofovir gel, while the other half were given a placebo. They were instructed to apply the gel 12 hours before and up to 12 hours after intercourse. Both groups were told the drug was experimental and were counseled to also use condoms or another means of HIV prevention.
Compared with the placebo group, women in the tenofovir group showed 39 percent fewer HIV infections. Within the tenofovir group, women who used the gel more than 80 percent of the time had 54 percent fewer infections than women who used the placebo gel with similar diligence.
“It’s refreshing and good news,” says virologist Charlene Dezzutti of the University of Pittsburgh. “A 54 percent protection rate in people who have used the gel consistently is excellent. I don’t think any HIV prevention measures will ever be 100 percent effective. You’ll always have people who don’t use gels regularly, and some people who don’t absorb the gel as well as others.”
The researchers say they intend to do research to confirm the study’s results, figure out why the gel didn’t protect more women and test the gel outside an experimental setting.