The world's largest AIDS conference began Monday in the nation's capital.
More than 2,000 scientists, policy makers, and AIDS patients will meet this week to discuss practical ways to help prevent the disease.
Much of the AIDS conference will focus on how to get treatment to all people with HIV. Good treatment can cut their chances of spreading the virus to sexual partners by 96 percent.
Those at the top of the list are gay and bisexual men, sex workers, and injecting drug users.
"AIDS is still in-curable, but it no longer has to be a death sentence. That is a tribute to the work of countless people around the world," Secretary of State Hillary Clinton said.
The leading U.S. AIDS researcher said Monday that science has provided the tools needed to reduce new infections without a vaccine.
Now countries must put them in place. The U.S. is donating $80 million to help poor countries reach that goal.
Dr. Anthony Fauci told the international conference that it won't happen overnight because "a lot of people, a lot of countries, a lot of regions have a lot to do."
Topping that list of tools is better treatment of people who already have HIV, so they're less likely to spread the virus.
But Fauci also called male circumcision a "stunningly successful" step, pointing to part of Uganda that's stressing that step.
More than 1 million people in America and some 34.2 million people worldwide are living with the disease.
The United Nations hopes to raise $7 billion a year to get to 15 million people in low- and middle-income countries by 2015.
However, funding has become increasingly uncertain as wealthier nations face harsh economic times.