"I think there have been some observational, smaller studies that suggested the same thing. So when you put these observational studies together with a 'gold standard' clinical trial, the findings are overwhelming."

The new standard of starting treatment at a CD4 count of 350 has already been embraced by the World Health Organization and the United Nations' UNAIDS program. The new treatment protocols come as the 18th International AIDS Conference is set to open in Vienna, July 18-23.

The study was conducted in Haiti, one of the world's poorest countries, with one of the highest rates of HIV infection outside Africa. Antiretroviral drugs have come down in price, but starting treatment earlier can still represent a lot of money. Nevertheless, Fitzgerald says it looks like a good investment.

"My strong belief is that it may in the long run save more money, that we're preventing a lot of tuberculosis," he says. "We're preventing people from going into the hospital. We're making people who would have been feeling sick and maybe not being able to work as much — are able to keep their jobs. So I think the tradeoffs are enough that it's really worth it to start early."

We reached Daniel Fitzgerald at his office at Weill Cornell Medical College in New York. The paper on early HIV treatment is published in the New England Journal of Medicine.