A cream, gel or pill that women can use to protect themselves from the AIDS virus is key to stopping the AIDS pandemic, Microsoft founder Bill Gates, who has given hundreds of millions of dollars to HIV programs, said.

Gates said he would step up funding for prevention research but said governments and other donors needed to do so, also.

?We want to call on everyone here and around the world to help speed up what we hope will be the next big breakthrough in the fight against AIDS ? the discovery of a microbicide or an oral prevention drug that can block the transmission of HIV,? Gates said in a speech to open the 16th International AIDS Conference in Toronto. ?This could mark a turning point in the epidemic, and we have to make it an urgent priority.?

A microbicide is a gel or a cream that a woman could use to protect herself against sexual transmission of the AIDS virus. And some studies suggest that certain HIV pills might help protect people from infection. The World Health Organization estimates that half of the 39 million people infected with the human immunodeficiency virus today are women, and HIV is mostly transmitted through sexual intercourse between a man and a woman. In sub-Saharan Africa, where 64 percent of all HIV patients live, more women are infected than men. Most children who are infected catch the virus from their mothers as newborns. There is no cure for HIV and no vaccine against it. ?The amount of money needed for universal treatment or prevention far exceeds the amount any individual government or foundation can provide,? Gates told a news conference.

Researchers at Family Health International believe a pill already used in HIV drug cocktails called tenofovir, made by the California-based Gilead Sciences Inc. under the brand name Viread, could keep healthy people from getting HIV. They will tell the conference about a study showing women can take it safely. And 16 potential microbicides are being tested in people, five of them in advanced studies. They range from gels based on carrageenan, taken from sea algae and already used widely in foods and toiletries, to HIV drugs put into a gel or cream that could be applied vaginally. A woman could use one quietly, without having to ask her husband or partner to use a condom or to abstain from sex.

?We need to put the power to prevent HIV in the hands of women,?Gates said. ?We are determined to help medical science discover these new drugs and get them to the people who need them.?