Gel reduces risk of HIV infection

A groundbreaking study delivers results that could lead to a major tool in preventing not only HIV, but another common sexually transmitted disease.

VIENNA, Austria, Wednesday July 21, 2010 – First time results from a South African study show that a vaginal gel containing the antiretroviral drug tenofovir can halve a woman’s risk of becoming infected with HIV during sex. But it appears that it is even more powerful in preventing genital herpes, a common viral sexually transmitted infection which itself increases the risk of acquiring HIV infection.

The gel cut HIV infection rates by 50 percent after one year of use, and by 39 percent after two and a half years, researchers at the Centre for the AIDS Programme of Research in South Africa (CAPRISA) said. The gel also resulted in a 51 percent reduction in genital herpes, a common viral sexually transmitted infection which itself increases the risk of acquiring HIV infection.

In the concept study, the gel was found to be both safe and acceptable when used once in the 12 hours before sex and once in the 12 hours after sex by women, aged 18 to 40 years. 

Explaining the herpes connection, one of the researchers Salim Abdool Karim who released the information at the 18th International AIDS Conference in Vienna, Austria said that nearly half of the women did not have the herpes simplex virus-2 (HSV-2) infection at the start of the study. Of this group, 58 of 224 women in the placebo arm of the study became infected with HSV-2, versus 29 of the 202 who received the gel.

And because herpes increases a person's risk of becoming infected by HIV, Abdool Karim said that “once confirmed and replicated, tenofovir gel has the potential to alter the course of the HIV epidemic”.

Nearly 20 years of research have gone into microbicides that can be controlled by a woman, independent of her partner. This microbicide study, UNAIDS said, could open new possibilities for HIV prevention.  

UNAIDS Executive Director Michel Sidibé said the results give hope to women.

“For the first time we have seen results for a woman initiated and controlled HIV prevention option,” he said. “If confirmed, a microbicide will be a powerful option for the prevention revolution and help us break the trajectory of the AIDS epidemic.”  

"We welcome the findings of the CAPRISA study. All new advances in HIV prevention, particularly for women are exciting. We look forward in seeing these results confirmed. Once they have been shown to be safe and effective, WHO will work with countries and partners to accelerate access to these products", said Dr Margaret Chan, Director-General of WHO.

About half of the people living with HIV in the world are women. In sub-Saharan Africa more women are infected than men. HIV is a major cause of maternal mortality. 

“Given high levels of ongoing HIV transmission to young women in high prevalence settings, it is urgent now to confirm these results so that a safe and effective tenofovir gel can rapidly be made available to women who want it,” UNAIDS said.

It added that in addition to rapidly moving to additional trials to confirm results, key issues that need to be addressed include: determining requirements for the approval by national drug regulatory authorities of this new indication for tenofovir; operations research on how to deliver and sustain product supplies within combination prevention programmes; determining the frequency of HIV testing; and accelerated studies to expand knowledge on the safety of the product particularly in young women (below 18 years of age) and pregnant women.   

To stimulate and prioritize rapid action, WHO and UNAIDS will convene an expert consultation in South Africa next month with women’s health and HIV prevention advocates, scientists, microbicide research teams and product developers, and public health experts to discuss the next steps with the product.