Taking daily doses of HIV-prevention pills or gels did not stop transmission of the deadly virus, in large part because the African women involved in the study did not follow the recommended treatment regimen, researchers said Monday at a scientific conference in Atlanta.
The results were linked to the low levels of use of any of the three tenofovir products provided to some 5,000 HIV-negative African women during the study period.
"No intervention is going to be effective if it's not used, and the point is that the majority of women" in the study "didn't use any of the study products as recommended," said Dr. Zvavahera Chirenje of the University of Zimbabwe in Harare.
The disappointing results come even as U.S. researchers announced Sunday a breakthrough on another front: A Mississippi baby born with AIDS apparently was cured completely after an aggressive treatment of retroviral drugs in the first days after birth. The case would be only the second documented case of an HIV-AIDS sufferer being judged completely free of the deadly virus.
The African study, known as Vaginal and Oral Interventions to Control the Epidemic, was a real-world test of a promising AIDS-prevention strategy known as "pre-exposure prophylaxis."
Scientists believe that if HIV-negative people who are at high risk for acquiring HIV will take proven prevention products every day, the drugs have the potential to "inhibit" growth of the virus, "thereby thwarting the establishment of permanent infection," according to the National Institute of Allergy and Infectious Diseases, one of the agencies in the U.S. National Institutes of Health that supported the African study.
The study involved more than 5,000 women in South Africa, Uganda and Zimbabwe, beginning in 2009. The women were asked to take a daily pill, either Truvada or Viread, containing tenofovir, or use a daily dose of tenofovir 1 percent vaginal gel. Women in control groups used placebo products.
The researchers thought the study participants would welcome an easy-to-use HIV-prevention product they could control, especially since most African women acquire HIV through sex with an infected male partner.
But testing showed that, on average, less than 30 percent of women used their anti-HIV products as requested. As a result, their HIV-acquisition levels matched or even exceeded the control groups.
Single African women younger than 25 were least likely to use the daily products and most likely to acquire HIV.
One of the frustrations of the study was that "we found women weren't using it, even though they were coming to the clinics and said they were using it," said Mitchell Warren, executive director of AVAC, a global advocacy group for HIV prevention.
"We know there's a huge need for these products. But need for these products does not equal use," Mr. Warren said. "We've got to really figure out how to help people both understand their risk and act on that."
Researchers said a dosing method that requires women to use the product as part of their sexual activity — rather than taking a product every day — may be preferable. This strategy has been supported by studies that have shown that when tenofovir is used before and after sexual intercourse, the risk of HIV infection is significantly reduced.
The results of African study were presented Monday at the 20th Conference of Retroviruses and Opportunistic Infections in Atlanta. The study conducted by researchers with Microbicide Trials Network, which is funded by agencies within the U.S. National Institutes of Health.
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