TORONTO, Ontario (CNN) -- During the 25 years of the AIDS epidemic, much of the focus has been on developing a vaccine or treatment, and prevention has sometimes seemed to take a back seat. But this week at the 16th International AIDS Conference in Toronto, the tables are turning.
During the keynote address at the opening ceremony Microsoft founder Bill Gates and his wife, Melinda, put the spotlight on prevention, especially for women.
Every day an estimated 6,000 women around the world are infected with HIV; they make up more than half of all new infections. They're especially vulnerable because every way a woman has to protect herself from HIV -- abstinence, and male and female condoms -- need her partner's cooperation. There are no options currently for women to use to protect themselves without her partner knowing.
"We need tools that will allow women to protect themselves. This is true whether the woman is a faithful, married mother of small children or a sex worker trying to scrape out a living in a slum," Bill Gates said. "No matter where she lives, who she is or what she does a woman should never need her partner's permission to save her own life."
Several options already are in clinical trials.
One is a microbicide gel or cream that a woman can insert in her vagina before sex. Five such products are in large-scale trials. Next year a product called Carraguard, which is being tested in South Africa,will be the first to complete large-scale clinical trials, bringing it closer to public availability.
While experts such as Dr. Zeda Rosenberg, head of the International Partnership for Microbicides, say microbicidal gels won't be 100-percent effective, even a little protection will have a benefit.
"If they're 30 percent effective, depending on how many women use it and how quickly it gets rolled out, you could save several millions of lives in the first three years," Rosenberg said.
Newer microbicidal gels are being created with medicines that are being used to treat HIV, such as Tenofovir and Truvada, a combination of Tenofovir and another AIDS drug.
Animal studies have shown that Tenofovir reduced the risk of infection, so researchers are putting it in a gel to see whether it will keep women from getting infected. Safety trials are still in the early stages in New York and Birmingham, Alabama.
The researchers say that if Tenofovir gel proves safe it will be available in about 18 months. Then more studies will determine whether it reduces virus transmission.
If microbicides work, researchers say, the earliest they will probably be widely available is 2010 because of licensing issues. So, other scientists are trying another approach that might be useable sooner.
They are studying the use of Tenofovir in pill form to see whether taking the medicine orally before high-risk behavior such as sex would block infection.
"We believe that microbicides and oral prevention drugs could be the next big breakthrough in the fight against AIDS," Bill Gates said.
A study from Ghana is finding the approach is safe. Larger studies on effectiveness are under way in Botswana, Peru and Thailand. The first results on efficacy are expected in 2007 or 2008.
Pills such as Tenofovir could offer protection not just for women. Men who were at risk for infection could also take the medicine if it proves successful.
But unanswered questions remain: Are there medical problems associated with long-term use of these pills? Will taking them for prevention increase the risk of resistance if people using them did become infected.
In other research focused on men, a study presented at the conference revealed that male circumcision can reduce by an estimated 60 percent the chance a man will get infected with HIV. The foreskin is rich in Langerhans' cells, which are easily infected with HIV. By removing the foreskin, those cells are also removed and the chance of infection is greatly reduced.
But in many countries there are cultural issues surrounding male circumcision that will need to be addressed before the practice can become widespread. Some experts also are concerned that men who are circumcised might be less likely to use a condom.
Results from other research may have more immediate help for women. A clinical trial in South Africa and Zimbabwe is testing whether a latex diaphragm can reduce the risk of infection.
Studies suggest that most HIV infections in women happen in the cervix, so researchers are investigating whether covering the cervix could protect women. Results are expected next year.
Treatment of HIV has been increasingly successful, and more developing countries are getting access to the medicines.
But that means people with HIV are living longer. And with 40 million people living with HIV and more than 4 million infections every year, finding new and easier ways to prevent infections is imperative, researchers and humanitarians say.
Christy Feig is a senior producer for the CNN Medical Unit.