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Studies show promise in curbing AIDS in Africa

In one finding, the use of a microbicide is shown to reduce chances of HIV transmission in women by more than half. Another indicates that financial incentives can delay girls' sexual activity.

July 20, 2010|By Thomas H. Maugh II, Los Angeles Times

For the first time in the bleak history of the AIDS epidemic on the African continent, researchers have identified two new approaches that could blunt the effects of HIV on women: a vaginal gel to block infection, and cash payments to delay sexual activity. Together, experts say, they might finally make headway against a disease that has already killed millions.

The approaches, described in separate findings released Monday at the International AIDS Conference in Vienna, are considered especially important because women have borne the brunt of the epidemic. Men rarely use condoms or other methods that might prevent transmission of the virus, and their wives and partners are generally powerless to convince them to do so. Further, girls and young women are often forced into sexual activity because of their families' abject poverty.

The more significant finding concerns the efficacy of a vaginal gel, containing a microbicide. The gel could place prevention squarely in the hands of women; unlike with a condom, their partners would not have to consent to its use, and might not even know it is being used. A clinical trial of the gel showed that it could block more than half of new infections if used regularly.

In the other study, researchers found that they could delay sexual activity in girls and young women by supplementing family income with modest amounts of money, as little as a few dollars a month. That delay led to a 60% reduction in HIV infections.

The money appears to allow families more economic freedom, ultimately delaying girls' sexual activity. Researchers hope such a delay will have a long-term effect on their overall health.

The results with the microbicide are particularly gratifying to scientists because more than 30 previous clinical trials of such agents have yielded little or no benefit.

"This is the first time we have seen any microbicide give a positive result," said Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases. "Given that women make up the majority of new HIV infections throughout the world, this finding is an important step toward empowering an at-risk population with a safe and effective HIV prevention tool."

Added Michel Sidibe, executive director of the United Nations' AIDS-fighting arm, "We are giving hope to women. For the first time, we have seen results for a woman-initiated and -controlled HIV prevention option. If confirmed, a microbicide will be a powerful option for the prevention revolution and help us break the trajectory of the AIDS epidemic."

An estimated 33 million people worldwide are living with HIV, two-thirds of them in sub-Saharan Africa; another 32 million have died of AIDS complications.

Previous attempts at producing a microbicide have used detergents or other chemicals that don't specifically target the AIDS virus. The new trial used the antiretroviral drug tenofovir, which is manufactured by Gilead Sciences Inc. of Foster City, Calif., and interferes with the replication of the virus.

The clinical trial of the microbicide — a 1% concentration of the drug incorporated into a colorless, odorless gel and distributed in a plastic applicator — was organized by the husband-and-wife team of Dr. Quarraisha Abdool Karim and Dr. Salim S. Abdool Karim of the Center for the AIDS Program of Research in Durban, South Africa.

They enrolled 889 sexually active women between the ages of 18 and 40 in the South African province of KwaZulu-Natal; about half received the gel with microbicide and half a placebo. The women were told to use the gel in the 12 hours before they expected to have sex and in the 12 hours afterward. The researchers collected applicators to monitor compliance.

The Abdool Karims reported online Monday in the journal Science and at the AIDS conference that the microbicide reduced new HIV infections by 39% and new genital herpes infections — which contribute to HIV transmission — by about half.

In the women who used the microbicide at least 80% of the time, the reduction in HIV infections was 54%. In contrast, among those who used it less than half the time, the reduction dropped to 28%. The only apparent side effect was mild diarrhea, which was uncommon.

The researchers are now attempting to find ways to improve compliance with the regimen. They're also testing different dosages of the active drug to see if that will improve efficacy. Other AIDS experts pointed out that the results need to be replicated before hopes get too high; subsequent studies might not yield such positive results.

Fauci and others said that the gel would probably have to obtain a higher efficacy, at least 80%, before it could be approved by the Food and Drug Administration for marketing in the United States. It will thus be several years before such a product could be available here.

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