Immunization Science

Polio Vaccine and AIDS

The article

Origin of AIDS: Contaminated polio vaccine theory refuted. Worobey M, Santiago ML, Keele BF, Ndjango JN, Joy JB, Labama BL, Dhed’a BD, Rambaut A, Sharp PM, Shaw GM, and Hahn BH. Nature 2004;428: 820

NNii explanatory note: Many scientists believe that Human Immunodeficiency virus (HIV), the virus which causes Acquired Immunodeficiency Syndrome (AIDS), is derived from a closely related virus in chimpanzees and arose by infection of a hunter. In 1999, a widely publicized book, The River: A Journal to the Source of HIV and AIDS by British journalist Edward Hooper, theorized that field trials of an early oral poliovirus vaccine were the origin of the global AIDS epidemic.

Hooper speculated that chimpanzee cells were used in the production of the experimental vaccine lots of type 1 oral polio vaccine developed by Hilary Koprowski, which was tested in the former Belgian Congo between 1957 and 1960. Hooper theorized in The River that the monkey cells used to prepare the vaccine were contaminated with chimpanzee cells and the chimpanzee immunodeficiency virus—and that ingestion of the virus during oral vaccination led to the human infection with a virus that was to evolve into HIV-1. The theory relies heavily on the coincidental recognition of cases of AIDS in the region near some of the sites where the vaccine was tested in Central Africa.

A large collection of scientific evidence is now available that permits rejection of this theory:

  • The same lot of vaccine also was tested in many people in Europe (for example, 7.2 million in Poland) without giving rise to HIV or AIDS.
  • Three independent laboratories examined several old vials of vaccine and showed only evidence of monkey cells; specifically there was no evidence of chimpanzee cells.
  • The presence of polio virus was confirmed but there was no evidence for any HIV-like virus.
  • Studies of the evolution of the origin of HIV have shown that the virus was first acquired by humans between 1915 and 1941, in an altogether different region of Africa.

The question

Is chimpanzee immunodeficiency virus present in chimpanzees in the vicinity of Kisangani, Democratic Republic of Congo and, if so, is it related genetically to HIV-1, as Hooper theorized?

The study

Researchers collected fecal samples from chimpanzees in the region, conducting molecular analyses to confirm the presence of the chimpanzee immunodeficiency virus and to identify circulating strain(s). They then compared the genetic sequences of the virus they found with the known sequences of other chimpanzee immunodeficiency viruses and HIV-1.

The findings

The researchers found chimpanzee immunodeficiency virus among the 97 samples that they tested, confirming that natural infection occurs among chimpanzees of the area. The virus that they found was a new strain of chimpanzee immunodeficiency virus and is clearly different than the strain from which all strains of HIV-1 were likely to have been derived.

The relevance/bottom line

The data presented in the study by Worobey and associates provide additional direct evidence that chimpanzees from this region were not the source of the human AIDS pandemic.

NNii’s comment

Current polio vaccines are not related to the experimental vaccine described in this article.

The theory that HIV arose from an early experimental polio vaccine has been firmly rejected.