http://www.mifami.org/eLibrary/Curtis-OriginOfAIDS-RollingStone.pdf

But there was another monkey virus that polio researchers missed. Between 1954 and 1963, an estimated 10 million to 30 million Americans and scores of millions of people around the world were exposed to a virus that infected the kidneys of Asian rhesus monkeys imported mainly from India. The virus survived the formaldehyde that Salk used to kill his polio viruses. Since 1961 researchers have tested monkeys for SV40 - so called because it was the fortieth such simian virus identified - before using their kidneys for vaccine production.

SV40 was delivered straight into people’s bloodstreams along with their Salk shots and via sugar cubes in field trials of the weakened living virus developed by Sabin. Though it was later shown to cause cancer in hamsters and to ‘‘immortalize’’ human cells in test tubes - thus predisposing these cells to cancer - SV40 has not been proven to generate illness in human beings. Nevertheless, researchers at Johns Hopkins recently discovered that when they injected cells treated with SV40 into ‘‘nude’’ mice, which lack an immune system, the mice developed Kaposi’s sarcoma-like tumors, similar to those afflicting many AIDS victims. Remarkably, considering the large numbers of people who received the SV40-contaminated polio vaccines, no one has conducted a major epidemiological study in the U.S. to discover whether there is any pattern of illnesses caused by the virus.

Still, there are some troubling statistical associations. In 1968 a scientist in Australia described a correlation between polio immunization and cancers in children past one year of age. Much later, German scientists found evidence of SV40 in 30 out of 110 brain tumors, and later reports indicated a jump in the frequency of brain tumors among those who had received vaccine contaminated with SV40. And SV40 has been associated with other human cancers as well.

But when Koprowski, Salk and Sabin were doing their initial vaccine development in the Fifties, little was known about the simian viruses, and there were no federal regulations stipulating that the viruses be grown in a specific type of tissue culture. No one knew then about retroviruses like HIV that might take years to develop, and so it was assumed that if no viruses had shown up in preparations after a couple of weeks, then those vaccines were clean.

In 1988, when researchers in the Washington, D.C., area reexamined an earlier study run between 1959 and 1965 on nearly 59,000 pregnant women, they found a startling connection: The incidence of brain tumors in children of mothers who’d been injected with the Salk vaccine was thirteen times greater than that of offspring of mothers who hadn’t had those polio shots. Stored blood serum from these mothers still existed, and it was retested. The tests seemed to exclude SV40 as the cause. But if not SV40, what about the Salk vaccine might explain the increased risk of brain tumors in offspring of vaccinated women? The researchers asserted that some other infection was probably the culprit. After all, they noted, the Salk vaccine was known to have been contaminated with numerous monkey viruses.