To the Editor,
In their letter of Dec. 7 ("Challenging a Theory"), doctors Stanley Plotkin and Hilary Koprowski "state categorically that no chimpanzee tissues were used by us for polio vaccine production". In so doing, they clearly hope to refute the central hypothesis of my book, "The River", that the administration of an experimental polio vaccine, CHAT, in central Africa in 1957-1960 may represent the occasion when the simian immunodeficiency virus (SIV) of the chimpanzee entered humans, and began adapting to become HIV-1, thus sparking the AIDS pandemic.
Although the doctors' personal assurance on this point is to be welcomed, it is not - by itself - enough. Uniquely for polio vaccines of the fifties, neither the passage history of CHAT, nor details of the primate species used to produce the vaccine, have ever been published. Dr. Koprowski has stated that records about the vaccine were "lost in a move", though the circumstances of that loss remain unclear.
It is surely time for a proper, independent investigation to be launched into how CHAT was made. The panel of experts which, in 1992, investigated an earlier version of the CHAT hypothesis of origin (at the request of the Wistar Institute, where CHAT vaccine was developed) was provided with only a single page of appropriate documentation from the 1957-1960 period by the Wistar. Yet major laboratories, as a matter of course, retain lab notebooks - either as originals, or on microfiche.
I would propose that the relevant Wistar notebooks from 1957-60 should now be made available for examination by independent experts. And since 70% of the CHAT vaccine administered in Africa was produced not at the Wistar, but in Belgium (at the Rega Institute in Leuven, and at RIT in Rixensart), similar information should surely be sought from these institutions. In addition, technicians who worked on CHAT vaccine during that period should be invited to contribute what they know.
Doctors Plotkin and Koprowski state that "the early cases of AIDS appeared where they would be expected to occur, in sites of relatively high population density". This fails to address the fact that although CHAT was administered only in the Congo, Burundi and Rwanda, 64% of the earliest African AIDS cases that can be traced came from the very same towns and villages where CHAT had been administered. Furthermore, 45 of the first 46 samples of HIV-1-positive blood from Africa (through 1980) came from places which were, or which lie within 90 miles of, CHAT vaccination sites.
The two doctors also question the timing of the viral crossover from chimps to humans, stating that other analyses suggest an earlier date that 1957-9. It needs to be pointed out that attempts to date the origin of HIV-1 based on the "molecular clock" technique would become invalid if there were, as I postulate, a number of near-simultaneous introductions of chimp SIV to man via the central African vaccination campaigns, rather than a single viral transfer. Recombination between different SIV or HIV variants is another factor that is known to
throw out molecular clock calculations, and the three earliest known sequences of HIV-1 (all, incidentally, from the Congo) appear to be multiply recombinant. I would welcome a hypothesis from one of the adherents of "single transfer" to explain this surprising detail.
Edward Hooper, Somerset, U.K.
[Edward Hooper is author of "The River: A Journey to the Source of HIV and AIDS", published by Little, Brown.]
NB "The three earliest known sequences of HIV-1" referred to above are ZR59 (from Leopoldville/Kinshasa, 1959; Z321 (from Yambuku, 1976); and MAL (from Kinshasa, 1985). Significantly, however, the patient from whom the third sequence was derived, a seven-year-old boy with prodromal AIDS, was "probably infected in 1981 after a blood transfusion, since his parents were [HIV]-seronegative". Taking 1981 as the relevant date would render this the third earliest HIV-1 (Group M) sequence in the world.
Polio vaccines and the origin of AIDS
in the section on The River.
It is located on the website on suppression of dissent.