December 1 is World AIDS Day – an event to raise awareness of the global AIDS pandemic.

According to the latest UNAIDS report, 33.3 million people worldwide are living with HIV.  22.5 million of them live in Sub-Saharan Africa.  But, in the past 10 years, HIV infections have dropped by 20 percent. Medical experts say the combination of new treatments and a greater focus on prevention has been a success story. 

According to specialists in the field and AIDS activists alike, in sub-Saharan Africa -- where efforts on raising awareness and relief is credited with saving 5 million lives -- the game changer has come as a direct result of massive U.S. funding that began in 2003.

While support for the funding has been bipartisan, U2's lead singer and humanitarian Bono credits former President George W. Bush with leading the charge on the issue.

"Even people who are snide and snarky about the United States of America have to admit that millions and millions of lives have been saved by American taxpayers," Bono told Fox News' Bret Baier.

As an international rock star, Bono has had the power to be the face and mouthpiece to millions of Americans and citizens worldwide. His ONE campaign advocates to world leaders, raises awareness of the disease, and pumps funds into fighting the epidemic and global poverty as a whole.

When Bono began his advocacy, the situation in Africa was bleak.  "It was seen as ridiculous, indeed, preposterous to get AIDS drugs to such people," he said.  "You know, it was too complicated.  The drugs were too expensive."

But, he reached out to the nation’s highest office and found allies in former Presidents Clinton and Bush and President Obama.

“President Clinton did an enormous job” making AIDs drugs affordable, Bono said.

Bono kept up his efforts when President Bush took office.

"We gathered together a compelling argument for why this was not only possible, but a moral imperative," Bono said.  "When you have this kind of chaos, the destruction of human lives for no good reason, it's very bad for everybody.  It's very bad for the world.  And I think President Bush was moved by his own compassion.  But I think he was also being hard-headed about it and saying, you know, America needs to show the world what it's for as well as what it's against."

“We started the process in mother to child transmission, which was an effective way to begin. But the numbers were so staggering—I wanted something…bigger,” President Bush said in an interview in his Dallas, Texas office.

So, in 2003, President Bush launched the President's Emergency Plan for AIDS Relief (PEPFAR), pledging $15 billion in aid over five years. 

"I was acting on national security concerns," Bush said. "There's nothing more hopeless than for a child to watch mom and dad die of AIDS and nobody helped, particularly the wealthy nations. And the enemy we face can only recruit when they find hopeless people. And so to provide hope to people as best as we possibly could in the developing world is a national security concern as well as a moral concern. The strategy wasn't working, and an entire generation of Africa was being wiped out. And I felt the United States needed to lead."

In 2004, 700,000 people in low- and middle-income countries had access to anti-retroviral treatment. In 2009, 5.2 million were being treated with the drugs.

"Being effective was the thing we had to prove -- that there could be measurable results, that if American taxpayers were going to fork out for this historic AIDS initiative that somebody like me could come back years later, which I have, and say, America, you're saving 5 million lives.

It's an extraordinary thing that you have done," Bono said.

Bono said President Obama continues to be "very supportive" of the program.

In a special World AIDs Day message, President Obama said, “Let’s also recommit ourselves to building on the tremendous progress we’ve made both in preventing and treating the disease and ending the stigma and discrimination that too often surround.”

The U2 singer said he is confident the United States will continue to be the world leader in the effort.

"To live by the admonition to whom much is given, much is required, I think we ought to do that individually. And I think if we do that collectively as a nation we're better off," Bush said.