US House Minority Leader Nancy Pelosi on Friday hailed major medical and scientific achievements in the fight against AIDS, but cautioned against becoming complacent.

"HIV is still adapting," she said in a speech that capped off the 19th International AIDS Conference, a week-long event here dedicated to ending the disease that has killed millions worldwide.

The disease has mutated over the years and tried to stay one step ahead of scientists and researchers fighting it, and it is "up to us" to adapt, she added.

Meanwhile, all conference participants -- 20,000 activists, researchers and scientists -- have "adapted to the challenge," taking a fresh approach and implementing new science, she said.

"Our decision to act changed the lives of many people," she said.

Indeed, the tide is turning on AIDS, she said, reiterating the conference's theme that the world is beginning to win the war against the disease.

"We must carry on with determination, hope and courage," she said, adding that, where there is new science that could help defeat the disease, the world has a "moral obligation to fund it."

She also trumpeted US President Barack Obama's controversial Affordable Care Act, also known as "Obamacare," for increasing coverage for those afflicted with the disease.

"We are delivering substantial protection," she said. "We have come a long way" since the first global AIDS conference in 1985.

Describing her constituency San Francisco, she recalled the early to mid-1980s when doctors first began discovering symptoms they had never seen before, which seemed like something out of a bygone historical era.

The disease took a toll quickly and soon people were attending two funerals a day, she said, adding that was when everyone knew it was a major health emergency.

She warned against cutting funding for HIV/AIDS research, billing it a "false economy" that would cost more in the future.

She praised conference participants and touted Obama's recent lifting of a travel ban on HIV positive people entering the United States, which made the conference possible.

"By all accounts this conference is a tremendous success," she said.