Lab test fails to find evidence of AIDS' origins

By EMMA ROSS, Associated Press

LONDON (September 11, 2000 5:41 p.m. EDT http://www.nandotimes.com) - Scientists say independent laboratory tests found no evidence to support the theory that an experimental polio vaccine used on about 1 million Africans in the 1950s inadvertently triggered the AIDS epidemic.

The findings, presented Monday at a conference at the Royal Society in London, found no evidence that the vaccine, administered between 1957 and 1961, contained any tissue from chimpanzees.

Scientists believe that HIV, the virus that causes AIDS, most probably originates from the type of SIV, or simian immunodeficiency virus, found in chimpanzees in western central Africa. But they don't know how or when the chimp virus got into humans.

The prevailing theory is that a hunter became infected after being scratched by a chimp when trying to capture it or after cutting himself while butchering the animal. However, some experts suspect that polio vaccine made with contaminated chimpanzee cells may have been the culprit.

In the latest tests, samples of four different supplies of the vaccine, including some used in the African immunization program, were tested for traces of genetic material from animals.

Two laboratories found the samples they tested were made using monkey tissue, but they found no chimp DNA, said Claudio Basilico, chairman of the microbiology department at New York University School of Medicine. Basilico chaired a committee set up by the vaccine's maker, the Wistar Institute in Philadelphia, to investigate claims that chimp tissue might have been used.

"Does this definitively rule out the vaccine theory? No, but it makes it more unlikely," Basilico said. He said record-keeping was sketchy at the time and that there may have been other samples not tested that were used in Africa.

The tests were also designed to find traces of SIV and found none. But that may not be important, Basilico said, because the virus could have died out after 40 years in a freezer.

The findings by the Max-Planck Institute in Leipzig, Germany, and the Pasteur Institute in Paris did not dampen the views of Edward Hooper, chief proponent of the polio vaccine theory.

Hooper contended in a 1999 book, "The River," that the Wistar Institute scientists might have used chimp kidneys contaminated with the virus to make some batches of the vaccine.

"This means nothing at all for the polio vaccine theory because different batches were prepared," Hooper said, adding that other, untested or missing batches might have yielded different results.

Two scientists who conducted the African vaccine trials denied any chimpanzee tissue was used to make the vaccine and branded Hooper's theory a "fantasy."

"We never used chimp kidneys," said Dr. Hilary Koprowski, who developed the vaccine. "I was there in 1957, and the author (Hooper) was not."

"I was working in the Wistar laboratory from 1957 to 1961 and I never saw or heard of chimpanzee cells" being used, added Dr. Stanley Plotkin, now a professor at the University of Pennsylvania.

Hooper quoted others involved in the research, such as lab technicians, hygienists and vets, who appeared to support his theory. One, a lab technician identified only as Juma, said kidneys were removed from chimps at the vaccine research station in Africa and sent to labs in Belgium and Rwanda.

Others contended that chimp kidneys were sent to the Wistar Institute in Philadelphia and that some of the vaccine was made in a laboratory in Stanleyville, in what was then the Belgian Congo, now the Democratic Republic of Congo.