Ending AIDS Epidemic Seen as Multi-Front War
Meeting Closes With Hope for New Methods

By David Brown
Washington Post Staff Writer
Saturday, August 19, 2006

TORONTO, Aug. 18 -- The scientists, health workers and activists fighting AIDS long ago gave up the idea they could kill the global epidemic with a single blow. But they are beginning to think it might be possible to bleed it to death with a thousand cuts.

That was among the things on the minds of 26,000 delegates to the 16th International AIDS Conference as they headed home and the huge, biennial, multi-ring circus struck its tent yesterday.

There are two large studies underway testing whether -- and by how much -- circumcision reduces a man's chance of becoming infected with the AIDS virus. Five different "microbicides" -- gels that block or kill the virus during intercourse -- are being tested on thousands of women in Africa. Five thousand are trying out an anti-HIV diaphragm.

Scientists are a year or two from learning how much they can cut the risk of HIV infection by treating people for herpes. Men and women on three continents are in experiments to see whether taking a single dose of an antiretroviral drug before sex can block infection.

And then there is the idea of just doing more of what the world has been doing furiously for the past two years -- putting more infected people on life-saving AIDS drugs. Studies presented this week provided yet more evidence that treatment may itself be a great strategy for prevention.

If even some of these approaches turn out to be successful -- and there is good evidence for all of them -- the cumulative effect could profoundly change the trajectory of the 25-year-old AIDS epidemic.

"Taken together, it feels as though we may have found a potential turning point. We may look back on this as an important moment," said Stephen Lewis, the U.N. special envoy for AIDS in Africa, as the conference closed.

The 25-year journey from AIDS's discovery in Los Angeles in 1981 to this conference is littered with the bones of bright ideas and great hopes -- and the bodies of 25 million who have died from the disease. Participants are hesitant to announce the dawning of an era of prevention that could eventually lead to the epidemic's end. That said, there was little doubt the meeting ended on a note of optimism and anticipation.

AIDS has been so disastrous in part because infected people survive a long time, are often unaware of their infection for years and are capable of transmitting the virus the whole time.

The strategy of getting everyone tested for HIV -- which is being pushed in U.S. cities as well as in African villages -- permits infected people to be identified early and to take steps -- both behavioral and pharmaceutical -- to make them less infectious.

If uninfected people can also use new protective strategies, the combined effect will be that each round of HIV infection will be smaller than the one before. The epidemic will contract. Eventually, it will crash.

The potency of AIDS treatment as a prevention tool is evident from studies of couples in which one person has HIV and the other does not. If the infected person has very little HIV in the bloodstream (a low "viral load" in medical parlance), the chance of the partner becoming infected is close to nil. The way to lower viral load is to take three-drug combinations of antiretroviral drugs -- "triple therapy."

In a Spanish study of nearly 400 such "discordant" couples, 8.6 percent of the partners became infected before the infected person started taking the drugs. In couples in which the infected person starting taking the medicines immediately, no partners became infected.

This happens in whole populations, too.

Data from British Columbia presented this week showed that after triple therapy became widely used in 1996, new HIV infections dropped steeply even though syphilis -- which is also sexually transmitted -- rose for six of the next eight years.

In one of the more provocative presentations, Julio Montaner, the director of British Columbia's AIDS center in Vancouver, showed a mathematical model of what would happen if all identified cases of HIV infection were treated. The line depicting the prevalence of HIV went essentially to zero by 2050.

The total cost of treating AIDS also took a clear downward turn starting in 2015, as the number of new cases fell off.

"I will say it three times: This is theoretical, this is theoretical, this is theoretical," Montaner told the conference as his "End-of-AIDS" graph was projected onto a half-dozen screens in the cavernous main hall of the Metro Toronto Conference Centre.

This conference's slogan was "Time to Deliver," a reference to the urgency with which triple therapy needs to be brought to the developing world. Only 1.5 million people there are getting it, even though 6.8 million need treatment immediately. According to data presented here, many get treatment only when their disease is so far advanced that the drugs are much less effective.

Nobody expects everybody in the world who has HIV to be treated -- not soon, or ever. Nevertheless, Montaner's point impressed many.

"Treated people just simply become less infectious. This is win-win. This is not a subject that requires debate," said Mark A. Wainberg, head of McGill University's AIDS program and one of the co-chairs of the meeting.

The real power of treatment's preventive effect is that it would synergize with other preventive strategies that may roll out a massive scale in the next five to eight years.

Microbicides got a huge rhetorical boost here, as the two star speakers, Microsoft founder Bill Gates and former president Bill Clinton, both touted their promise.

Results are expected over the next three years on the ones now in field tests, which block HIV in nonspecific ways. However, researchers reported early tests of a vaginal ring imbedded with an antiretroviral compound called TMC120 that specifically kills HIV. A woman could keep the ring in for a month, and it would leach out the compound that entire time, protecting her. Further studies, including testing whether African women would accept such a device, are planned.

Also awaited are the results of two studies, underway in Africa and North and South America, testing whether daily doses of the drug acyclovir reduce the risk of HIV infection in people with genital herpes, and in their partners. Herpes infection doubles a person's chance of acquiring HIV and increases an infected person's chance of transmitting it fivefold.

Two big studies of circumcision, which earlier research suggests reduces a man's chance of getting HIV by 60 percent, will have results by the end of next year.

"We think that's great," said Mark R. Dybul, an AIDS physician recently sworn in as the head of the Bush administration's global AIDS program, operated out of the State Department. "You can't just have a treatment program. You have to have prevention and care and treatment."

The next conference will be held in two years in Mexico City.