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(CNN) - Microsoft co-founder Bill Gates, now co-chairman and trustee of the Bill and Melinda Gates Foundation visited Washington, D.C., Monday, attending President Barack Obama's remarks on World AIDS Day at the White House.
The Gates' foundation has given billions of dollars to HIV research and grants. While much progress has been made, Bill Gates says eradicating the disease entirely, or having an "AIDS-free generation," as U2 lead singer Bono said Sunday, is still a far way off.
"We are going to be living with some level of AIDS for decades to come," Bill Gates told CNN's "The Lead with Jake Tapper."
More than 30 million people around the world live with HIV.
"We don't have a cure and so we have to keep them on drugs to keep them alive, and that requires not only generosity, but getting very innovative about how we reach that kind of a number. We need a vaccine, or a tool to prevent people from getting infection," said Gates.
Gates left Microsoft five years ago so he could work full time on giving his money away. He and his wife topped Forbes' list of America's top givers; Forbes estimated they gave away nearly $2 billion in 2012 alone.
Gates was a pioneer in technology, and says Amazon CEO Jeff Bezos' goal to develop a viable drone delivery system is "optimistic," but lauds Bezos' ambition.
"It's great that people have dreams like that. If we can make the cost of delivery easier, then it's not
just books, it's getting health supplies out to people in tough places," said Gates.
"Drones overall will be more impactful than I think people recognize in positive ways to help society," said Gates.
For more of our interview with Bill Gates, including how much he and his wife plan to leave their children, watch the video above.
CNN's Jessica Metzger contributed to this report.