More than a decade of failure and frustration ended Monday with a report that a new vaginal gel gives women the power to reduce their risk of contracting HIV and genital herpes without relying on their male partner to use a condom.
Gilead Sciences' antiviral drug tenofovir, which is widely used for treating HIV, the virus that causes AIDS. Applying the 1% tenofovir gel 12 hours before and 12 hours after sex reduced a woman's risk of HIV infection by 39% over the course of 2½ years.
The gel also reduced the risk of genital herpes by 51%, an unexpected bonus because women with herpes are twice as likely to be infected with HIV.
"We now have a product that can potentially alter the epidemic and save millions of lives," says Quarraisha Abdool Karim of the University of KwaZulu-Natal in South Africa, who co-wrote the study with her husband and university colleague, Salim Abdool Karim.
At this level of protection, the researchers say, widespread use of the gel could prevent 1.3 million infections and more than 800,000 deaths in South Africa alone over the next 20 years. The findings were to be released today at the 18th International AIDS Conference in Vienna and in the online edition of Science.
AIDS researchers and advocates who have grown accustomed to failure, or worse — one promising vaginal gel actually was found to boost the risk of infection — hailed the report.
In the study, 889 sexually active women ages 18 to 40 were given either the tenofovir gel or a placebo. Thirty-eight of the women in the tenofovir group were infected with HIV, compared with 60 in the placebo group. Of 434 women who did not have herpes at the start of the trial, 29 of those using tenofovir became infected vs. 58 using a placebo.
The gel worked best in the women who used it most consistently. Women who used the gel at least 80% of the time were 54% less likely to become infected, cutting their risk of HIV by more than half.
Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, says the study marks a "significant conceptual advance" in efforts to give women the tools they need to protect themselves.
"The level of protection isn't as high as we hoped it would be," Fauci says, "but there are a lot of things we can do to change that. The degree of the effect was related to the degree (to which women used the gel.) You may want to use it more often. You may want to put it in a vaginal ring."
Halima noted that the pipeline of microbicides may include drug combinations similar to those now used for HIV treatment. Fauci says his institute is sponsoring a complex trial that compares patients using tenofovir gel daily with those taking oral tenofovir or Truvada, a combination of tenofovir and Emtriva, also made by Gilead Sciences. Results won't be available for at least a year, he says.
Bloggers Note - Despite significant challenges in developing an immunization for HIV, this advance may be critical to saving lives for women. Additionally, this success will stimulate industry and research for additional advances.
HIV positive - evidence of exposure to HIV
AIDS - evidence of disease from HIV infection
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