A new vaccine combination tested in Thailand seems to have lowered the rate of infections by more than 30-percent. While that may sound like a modest rate, it's progress that's been a long time in coming.

It could be the long-awaited breakthrough in the war against HIV and AIDS, a vaccine that seems to have shown a modest success. Clinical trials in Thailand have sent a wave of cautious optimism throughout the medical world.

"Even though it's a very modest effect, it at least proves the concept that it can be done, and our work lies ahead of us," said Dr. Anthony Fauci.

The multi-year study of 16-thousand people, conducted by the Thai Health Ministry and the U-S Army combined two existing drugs. The result: a thirty-one percent drop in infections.

According to Dr. Fauci, "when you have a vaccine, you really like to see a vaccine that's sixty, seventy, eighty percent effective - or even more."

Still, after years of failure this study raises the bar and raises hopes. "It's been, I guess, 24 years now of sustained efforts to try to develop an Aids vaccine.

But I don't think we know enough about this to know whether it's really a first step. But it could be," said Dr. Michael Lederman, an HIV researcher with University Hospitals, in Cleveland.

In Washington, DC, where the HIV and AIDS rate has topped three percent there was a ribbon cutting at a new clinic. Actor Blair Underwood has been raising awareness and money for aids causes since the 1980s.

Today Underwood said: "thirty-eight million people around who are HIV - who have HIV or aids. Thirty-eight million. So anything that is promising to change that statistic is a good thing."

One study, some modest results, and big hopes that researchers are a step closer to beating AIDS. Researchers are hoping to learn more about this study next month, at an international conference in Paris.