A safe and effective gel allowing women to protect themselves from the AIDS virus may be available by 2010 if current trials involving thousands of women are successful, researchers said Sunday.

Gita Ramjee, director of the HIV prevention research unit at South Africa's Medical Research Council, said microbe-killing vaginal gels offered huge potential for stemming the epidemic, especially in societies where men are reluctant to use a condom.

Ramjee said that five separate clinical trials were underway involving 12,000 people in South Africa and thousands in other countries. Results should be ready in the next two years, she said.

"We have waited 25 years to address the epidemic, so 2008 is really not too much longer to wait," she told a press conference before an international conference on microbicides.

She said that if governments fast-tracked the regulatory approval process, the gels might be on the market by 2010 — although she cautioned this was the earliest anticipated date.

The conference co-sponsored by the World Health Organization brings together more than 1,000 scientists and researchers from around the world.

HIV infection is rising more rapidly among women than men in many parts of the world. Half of all adults living with the virus that causes AIDS are female, according to U.N. figures.

In sub-Saharan Africa, home to more than 25 million of the nearly 40 million people infected around the world, women account for nearly 60 percent of infections, with most acquired through heterosexual intercourse. Yet strong taboos still exist on the continent against the use of condoms.

The London School of Hygiene and Tropical Medicine has calculated that a microbicide that is 60 percent effective against HIV and used by only 20 percent of women in 73 developing countries over three years could prevent 2.5 million infections.

Microbicides can take the form of a gel, cream, sponge or ring that releases an ingredient that can kill or deactivate HIV during intercourse.

Coinciding with the start of the conference, South African AIDS activists launched a new campaign to try to prevent 2 million new AIDS infections by 2010.

The Treatment Action Campaign — which until now has focussed on improving access to medication — said it would press the government to provide more condoms and improve sex education.

"There is a crisis of prevention in this country," said Zackie Achmat, president of the campaign.

"There are 1,400 new infections every day. That must stop," he told a crowd of about 1,500 activists.

Up to 6 million South Africans are infected with HIV, the highest number of any country. It is projected that 2.5 million more may become infected by 2010.