AIDS cannot be halted through treatment alone, and more prevention tools, in particular a vaccine, are needed to move seriously toward ending it, philanthropist Bill Gates said Monday.
While the Microsoft tycoon applauded efforts to get more people worldwide on antiretroviral drugs -- and said his foundation funds both research and care -- he noted more is needed to stamp out the deadly disease.
"No one should think that we have got the tools yet. We will get the tools but only if we stay the course in terms of the scientific investments," Gates told the International AIDS Conference in the US capital.
His Bill & Melinda Gates Foundation has committed more than $2.5 billion in HIV grants to organizations around the world, and has also committed more than $1.4 billion to the Global Fund to Fight AIDS, Tuberculosis and Malaria.
Gates spoke to the conference, the world's largest gathering of AIDS scientists and advocates, as part of a panel on how to improve efficiency in funding of the three-decade-old disease that has killed 30 million people.
Gates said research toward a vaccine is "very exciting" but noted that even if a vaccine were introduced it would take time before the effects would be seen in the larger population.
"If you get a vaccine say in 10 years then the number of people you need to put on treatment is reduced in about 18 years," he said.
"Unfortunately there is this unbelievable lag time that comes out of that."
More than eight million people in low and middle income countries were on antiretroviral treatment in 2011 according to a UNAIDS report released last week, making up about half of those in need worldwide.
But Gates warned that no amount of funding can come up with enough money to treat everyone infected.
"It is clear that even if you take the most efficient way of doing this work -- the number of people who will eventually need to be on treatment, the amount of money we have is not enough to treat those people," he said.
"The world will make a decision how much those lives matter. And we are in a period of incredible uncertainty right now," he added.
"Just the uncertainty alone creates a certain instability."
Gates urged continued involvement by the AIDS community and reiterated the importance for nations and donors to support research, but also expressed support for ongoing treatment initiatives in the meantime.
"Now if somebody could cure AIDS -- which unfortunately that's very much a long shot," he said.
"There are people who are working it but... it is not in the cards at least any time soon, that is why this treatment imperative is so dramatic."