ROME -- The issue is drugs.
Everyone at the 2011 meeting of the International AIDS Society here agrees that there are not enough available antiretrovirals even to treat all those who will certainly die soon without therapy.
But now there is robust and compelling evidence that expanding treatment would not only help individual patients but also could slow -- and perhaps halt -- the 30-year-old HIV/AIDS pandemic.
A landmark study, formally presented here for the first time, showed that treatment of HIV patients almost completely blocked their ability to transmit the virus.
The obvious implication was that widespread treatment would slow the relentless pace of infection that drives the pandemic -- an implication that was not lost on the audience, which gave the investigators a standing ovation.
But the meeting also has heard positive results from studies of another approach -- so-called pre-exposure prophylaxis or PrEP, which focuses on people without HIV infection.
"There is a tension" between advocates of the two approaches, according to Julio Montaner, MD, of the B.C. Centre for Excellence in HIV/AIDS in Vancouver.
But all of the evidence to date, he told MedPage Today, suggests that "the best, most solid investment in stopping the epidemic is to invest in treatment now, massively, as much as we can."
PrEP, he argued, may have a role, but only as a "very targeted" approach, aimed at people who for one reason or another are at high risk and can't control their exposure to the virus.
"It's excellent news that there are other modalities available and in some circumstances they may be valuable," he said. "There are many ways you can skin this cat."
But in essence, he and others said, the risk of PrEP is that it will divert already scarce resources from expanding HIV treatment.
Montaner, a former president of the AIDS society, has long been an advocate of "treatment as prevention," a position initially based on mathematical modeling and some clinical evidence from experiments he and colleagues conducted in the Canadian province of British Columbia.
The HPTN 052 trial, which showed that treating the infected partner in a so-called discordant couple reduced the risk of transmission by 96%, is a major piece of evidence that Montaner and his colleagues were right.
But three trials have also showed that, in some circumstances, giving uninfected people a prophylactic dose of anti-HIV medication reduces their risk of acquiring the virus.
And Bob Grant, MD, of the University of California San Francisco -- who led iPrEx, the first of those trials -- argued that the two approaches are not in competition. Indeed, he said, use of pre-exposure prophylaxis may paradoxically "enable the roll-out of early treatment."
In the first place, Grant argued, the availability of PrEP will be another incentive for people at risk to get tested for HIV. If they're positive, he told MedPage Today, they can get treatment, and if they're negative, they have another way to increase their chances of staying virus-free.
Second, he said, the use of PrEP will reduce the "stigmatization" that is still associated in some places with HIV and anti-HIV drugs.
In any case, Grant said, treatment requires, by definition, that a person is aware of his or her HIV status, and many are not. Indeed, in the U.S., the CDC estimates that 200,000 people are HIV-positive but don't know it and that they are responsible for about half of all new HIV infections.
But the sexual contacts of those people could be protected by PrEP, he noted, even though treatment is impossible.
"We need more resources, make no mistake," said Mitchell Warren, of the New York-based advocacy group AVAC. But the debate here is focusing a "new lens" on exactly how resources should be used, he told MedPage Today.
The science is pretty much solid, Warren said, adding the "agenda for the future is what we do with those results."
And he suggested that flexibility -- rather than a one-size-fits-all approach -- may be the way forward. "We need to embrace the niche -- we can have tremendous therapeutic impact if we understand how to address the niches," he said.
Montaner, though, defended his "big picture" approach. Treatment will "stop death, stop progression, and stop transmission," he said, while PrEP only works in defined situations.
"The person who is positive carries the prevention within him- or herself," he said, but the "logistic problems" of PrEP as a large-scale public health intervention are insuperable. That said, he agreed that a necessary first step is widespread testing to find those who are HIV-positive but don't know it.
One objection to the interpretation of the HPTN 052 study has been that it really only applies directly to couples -- mainly married and heterosexual -- in which one partner is infected and the other is not.
But that misses a key point, according to Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases.
"If you're infected and you're having sex with an uninfected person, that's by definition a discordant couple," he told reporters.
Fauci added that there has been a tension between HIV treatment and prevention. "We should just forget about that," he said, "because treatment is prevention."