Report from the AIDS/Poliovirus Advisory Committee

JONFHDENTIAL
the virus prevalent in central Africa, U.S., and Europe; it is also responsible for most
cases of AIDS worldwide. In contrast, HIV-2 is less prevalent and is largely confined
to west Africa. HIV-2 is closely related to SIV of sooty mangabey monkeys and is
generally believed to have arisen by cross-species infection from monkeys to
humans in west Africa. Indeed, a recent report (Khabbaz et al., Lancet 340:271-273,
1992) has shown that SIV has infected at least one laboratory worker, consistent with
laboratory observations that SIV can grow in human cells. However, a retrovirus
closely related to HIV-1 has never been identified in monkeys.
4) Bridging the evolutionary distance between SIVs and HIV-1. Although
HIV-1 and the known SIVs from green monkeys, sooty mangabeys and mandrills
are evolutionarily related, their nucleotide sequence homology is only about 40%. It
is the view of many experts in the field that the evolution of SIV into HIV-1 was a
long process, measurable more in decades or centuries than in a few years. SIV from
sooty mangabey monkeys and HIV-2 are more closely related, but the predominant
virus in the AIDS epidemic is HIV-1. The earliest evidence of HIV-1 infection date
to 1959 (a seropositive individual in Zaire, and a seaman who died in 1959 with
typical AIDS symptoms and later found to have been infected with HIV-1). It is
extremely unlikely that the evolutionary gap between HIV-1 and any known SIVs
was bridged in less than two years. Moreover, we have investigated further details
of the earliest documented case of HIV-1 infection, the merchant marine mentioned
above, who was symptomatic in 1958 and died of AIDS in 1959 in Manchester,
England (G. Williams et al. Lancet, 1960; ii:951-955; Corbitt et al. Lancet, 1990, 336:51).
It appears that this man travelled abroad to Gibraltar and Northern Africa beginning
in 1955. However, he had returned to England by the first half of 1957 before the
Congo trial was begun. Therefore, it can be stated with almost complete certainty
that the large poliovaccine trial begun late in 1957 in Congo was not the origin of
AIDS.
5) Testing of the vaccine samples used in the Congo trials. Various articles in
the press have declared that the Curtis' hypothesis could be easily verified by testing
aliquots of the vaccine(s) used in the Congo trials, if these samples can still be found.
Unfortunately, things are not so simple. As stated above, testing of a master seed or
related vaccines will not be sufficient, as the contamination with SIV (if any) would
be likely to have occurred during the preparation of the actual vaccine lots used.

Thus, the vaccine samples will have to be conclusively identified as the ones used

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