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Stanford Report, July 26, 2000

Researchers challenge dissident views on AIDS' cause  


Science converged with politics earlier this month at the 13th International AIDS Conference in Durban, South Africa, where physicians and scientists from around the world came armed with a document stating unequivocally that HIV causes AIDS.

Some 5,000 scientists, including Stanford's Thomas Merigan, MD, signed the so-called Durban Declaration, a 920-word document stating that the evidence HIV causes AIDS is "clear-cut, exhaustive and unambiguous." The document was published in the journal Nature on July 6, just three days before the opening of the conference.

The declaration was designed to counter views courted by South African President Thabo Mbeki that there might be another cause for AIDS. Mbeki had stunned the world's scientific community by giving credence to dissidents such as Peter Duesberg, a cell biologist at the University of California, Berkeley, who for years has propounded theories that AIDS is caused primarily by use of illicit drugs or by antiviral drugs such as AZT. Mbeki, seeking a way out of the AIDS epidemic that is crushing South Africa, had invited Duesberg and other dissidents this spring to sit on a scientific advisory panel convened to address the country's crisis.

Around the same time, HIV specialists around the world began organizing to try to persuade Mbeki that these dissident views were misguided, said Merigan, the Becker Professor of Medicine and director of the Center for AIDS Research at Stanford. Merigan was one of 250 physician/scientists who served on the organizing committee for the declaration, which was signed by prominent researchers from the United States and from other nations now in the grip of AIDS, such as Russia, Thailand and several African nations.

"The idea was to get a broad concensus behind the basic principles of how HIV causes AIDS," Merigan said. "We felt that would be useful and would prevent confusion in the African sub-continent because it was clear Mbeki was going beyond first principles ­ that he was really questioning things the scientific community had settled years ago."

The declaration appeared to have little positive impact. In his speech to the conference, Mbeki did not directly address the controversy but focused on South Africa's poverty and the generally poor health of the population. He has suggested that other biological circumstances might be at work in the country's AIDS epidemic. Some 20 percent of the country's young adults are now infected with the virus.

Merigan said that while nutrition, poverty and overall health are surely factors in the South African epidemic, that does not negate the fact that the virus is the underlying cause of infection.

"I do not contest the fact that there is poverty and economic constrictions and concurrent diseases that might accelerate the AIDS process or even the transmission of AIDS, and we have to change our strategy in countries to consider those things," Merigan said. "We have to find new solutions for Africa. On the other hand, that doesn't mean you have to think there's some new cause."

Mbeki's government also stunned physicians at the conference by refusing a pharmaceutical firm's offer to supply free nevirapine, an AIDS drug, to pregnant women and their newborns. Because of concerns about side-effects, the government has discouraged use of nevirapine and AZT, which have been shown to dramatically reduce the chance of mother-to-infant transmission.

"I agree that there is a need for something different [in the approach to AIDS in South Africa], but I think that as far as stopping the spread to babies, they should be doing that if the drugs come free. It's completely wrong if they don't," Merigan said.

Merigan did not attend the conference but visited South Africa for a week in May to explore the possibility of testing a new immunomodulator drug at several sites there. The drug represents a new, less expensive approach that would require injections only once a month or so, in contrast to the current standard of therapy in this country, which involves daily use of a cocktail of costly drugs. Merigan met with the director of South Africa's AIDS program, an obstetrician-gynecologist who told him the country's treatment and prevention programs are still being carried out under the assumption that HIV is responsible for the disease.

"She reassured me that yes, we are going about control mechanisms as if the virus causes the disease," Merigan reported.

Nonetheless, he said he remains disappointed by the government's official response to the epidemic, particularly given that traditionally solutions to problems on the African continent have emanated from South Africa, which has a stronger economy and is more developed than its neighbors.

"We scientists are puzzled by the government's position," Merigan said. "There must be something driving it that we cannot see from our point of view." SR