The U.N. health agency said it hoped the measures would lead to a huge increase in the number of people gaining access to the drugs. Its goal is for three million people with the virus in developing countries to get the medicines they need by 2005. Currently less than five percent of the estimated six million people who need treatment get it.
"It's important to see the guidelines and list of essential drugs as part of a wider strategy," said Bernhard Schwartlaender, head of WHO's HIV/AIDS program. "I believe it will have a dramatic impact."
Since AIDS was first reported, more than 20 million people have died as a result of HIV infection, 3 million of them last year. An estimated 40 million are infected with HIV, the virus that causes AIDS, more than 90 percent of them in developing countries.
In wealthy countries, an estimated 1.5 million people live with HIV, many of them productively, thanks to drugs. In the United States, the introduction of triple combination antiretroviral therapy in 1996 led to a decline of 70% in deaths attributable to HIV/AIDS.
Poor countries don't have that option, even though agreements with pharmaceutical companies and competition from cheap generic versions have slashed the price of the drugs in the past couple of years.
Schwartlaender said the fact that antiretrovirals were now on the list of essential medicines could be "used as a tool for negotiation" with drug companies for further price reductions.
WHO's list of essential medicines contains 325 drugs, including household names like aspirin and penicillin. An expert committee meets every two years to update the list and at its meeting last week decided to list 12 antiretrovirals, including nevirapine and zidovudine.
"It should dispel any questions about the safety, effectiveness and public health relevance of these drugs," said Jonathan Quick, head of WHO's essential drugs program.
For instance, until last week, the South African government had argued AIDS drugs were unproven and too toxic to distribute. In a policy change, the Cabinet endorsed their use as helping to prolong the lives of some AIDS victims.
Cost aside, the antiretrovirals pose problems in developing countries because of the complexity of the treatment regime, which can involve 12 to 15 drugs in triple combination.
The WHO guidelines are meant to simplify and standardize this and make the experience of rich countries relevant for impoverished societies.
The WHO action came as health experts and government representatives gathered in New York for a meeting of the Global Fund to Fight AIDS, TB and Malaria which is meant to finance projects aimed at curbing the diseases that hit the poor hardest.
"The scale of devastation caused by HIV/AIDS is unmatched," said Peter Piot, executive director of UNAIDS. "But I believe even the world's poorest countries are on the brink of making substantial progress with quality treatment and effective prevention programs and it is up to the international community to redouble our support for their efforts."
By Clare Nullis