Mystery of AIDS Origin Remains After Scientists Discount 'Hooper'

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Huntly Collins, Knight Ridder Newspapers; The Macon Telegraph, September 17, 2000

© 2000 The Macon Telegraph

Until last year, the name Edward Hooper would have registered with virtually no one in the field of AIDS research.

But in 1999, Hooper catapulted himself into the limelight with a 1,070-page book, which argued that scientists from Philadelphia's Wistar Institute, testing a polio vaccine in the Belgian Congo in 1957-1960, may have unwittingly started the AIDS epidemic.

On the surface, Hooper's claims seemed to have merit. The oldest known case of AIDS occurred in a man from Kinshasha, the former Leopoldville, near the mouth of the Congo River. His blood, drawn in 1959, later tested positive for HIV, the virus that causes AIDS. No earlier case of HIV-positive blood has been identified.

What's more, most of the other early cases of HIV, dating back to the 1970s and early 1980s, also occurred in Congo, Rwanda and Burundi -- the former Belgian Congo. And most of those came from cities or towns close to where former Wistar director Hilary Koprowski tested his oral polio vaccine.

Koprowski also maintained a chimpanzee colony -- known as the Lindi Camp -- just outside Kisangani, the former Stanleyville, which was headquarters for the vaccine trials. Since scientists now know that HIV originated in chimpanzees and was then passed on to people, it wasn't much of a leap for Hooper to speculate that Koprowski's vaccine may have been grown in the kidney cells of the chimps kept at Lindi and become tainted with SPIcpz, the chimp version of AIDS, which then got passed on to people through the vaccine.

Perfectly logical but, as it turns out, probably wrong.

Theory doesn't add up

Last week, during two days of heated scientific debate at the Royal Society of London, Hooper's claims were shot down by a withering display of facts and cutting-edge genetic studies.

The weight of the evidence indicates that:

--The vaccine was cultivated in monkey kidneys, not chimps;

--Some of the early cases of HIV occurred in areas of the Congo where no one was vaccinated, while some of the most heavily vaccinated areas had no cases of HIV;

--The beginning of the AIDS pandemic goes back to 1930, decades before Koprowski and his team set foot in the Congo, according to three scientific groups who each used different methods to date HIV's "molecular clock."

If that weren't enough, tests conducted on the last remaining vials of polio vaccine used in Congo -- announced by the Wistar Institute last Monday -- found no HIV or SIV in the samples.

Another test confirmed that the polio virus used to produce the vaccine was grown in monkey tissue, not chimp cells.

The evidence, AIDS experts agreed, delivered a serious, if not fatal, blow to what's come to be called "Hooper's theory."

"It's like a baby that was pretty sick when it went into the meeting. It squawked a lot and now it's dead and has finally been buried," said John Moore, a leading AIDS researcher at the Cornell University Medical Center in New York.

If and when the origin of AIDS is finally pinned down, Hooper's claims are likely to be but a footnote in that story. But the fact remains that Hooper, a man with no formal training in the science of AIDS, managed to get the attention of both the public and AIDS researchers, prompting an extraordinary meeting of one of the world's most esteemed scientific bodies.

How did that happen?

In part, Koprowski himself lent credibility to Hooper's endeavor when he sued Rolling Stone magazine and the Associated Press over a 1992 story that made many of the same claims Hooper made in his book. Those lawsuits, later settled out of court, gave the impression that Koprowski was trying to quash a full investigation into the possible link between his polio trials and the origin of AIDS.

The lawsuits -- and threat of lawsuits as Hooper was later researching his own book -- roused the ire of key scientists, particularly in Britain, who felt the polio-vaccine theory about AIDS, even if it turned out to be badly off the mark, needed to be examined.

One of those scientists, evolutionary biologist William Hamilton of Oxford University, in the forward to Hooper's book denounced the threat of lawsuits and the closing of ranks by medical journals that refused to give Hooper's ideas a platform.

"Again it is time for us to wake up and consider what is happening to freedom of discussion and to the spirit of science," Hamilton wrote.

Spirit of science

Hamilton organized the Royal Society symposium, giving Hooper an opportunity to sit alongside esteemed scientists and make his case.

Wistar, too, gave life to Hooper's theory. The institute could have ended much of the debate by testing its polio vaccine samples nearly a decade ago when controversy first arose about the possible link between the Congo trials and the rise of AIDS.

But an outside scientific committee appointed by Wistar after the Rolling Stone article concluded that such tests weren't necessary because there was documented evidence of an HIV case -- a sailor from Manchester, England, who had traveled to Africa -- that predated the polio vaccine trials.

Later, however, that case was determined to be wrong, probably the result of a laboratory contamination. That left the 1959 Kinshasa man as the earliest known HIV infection, reviving the possibility that the vaccine trials may have sparked the epidemic.

Still, Wistar did not test its samples. Institute officials have declined to explain why, but it is widely believed that the organization was wary of doing anything that might lead to another fight with Koprowski, who had sued the institute, alleging age discrimination, after he was fired as Wistar director in 1991.

Only after Hooper's book began creating a furor did Wistar agree to have their 40-year-old polio vaccine sample tested by three independent labs, none of which last week reported finding any contamination.

The sheer heft of Hooper's book, with its detail about the polio vaccine trials in Congo, also made it impossible for scientists to ignore his claims. All told, he interviewed hundreds of people and pored over hundreds of documents, traveling to several continents to follow every lead.

Still, in the end, Hooper turned up only circumstantial evidence, which he used to build a highly speculative case. He has no proof, for instance, that chimp kidneys were extracted at Lindi and shipped to Philadelphia to grow the polio vaccine used in Congo.

He merely knows that chimps were housed at Lindi; that a former Lindi worker says organs were extracted but isn't sure they were kidneys; that the former veterinarian at Lindi was told by two Belgian doctors that they suspected chimp kidneys were being used to grow the vaccine, and that a shipment of chimp kidneys went from Lindi to Children's Hospital of Philadelphia.

Monkeying around

Against that, Dr. Stanley Plotkin, former Wistar deputy director, last week presented affidavits from everyone still alive who worked on the polio vaccine. All 16 assert that monkey kidneys, not chimp kidneys, were used to grow the vaccine.

The chimps at Lindi were used to test the vaccine for safety and efficacy, Plotkin said. And the shipment of chimp kidneys, he said, was for research that CHOP was conducting to find the causative agent of hepatitis.

"One can be precise without being accurate," Plotkin told the symposium. "The issue is not whether it "might have happened, but whether it "did happen."

Scientists are eager to move onto the still unanswered questions, among them: Exactly how did a chimpanzee virus get into people? Did a hunter cut himself butchering a chimp? Could just one such event spark an epidemic?

If the virus comes from a type of chimp found only in west-central Africa, why is it that the first AIDS cases arose in Congo, hundreds of miles away?

And why -- if people have been killing chimps for food for centuries -- didn 't an epidemic hit earlier?