From: Robert J. Bradbury (bradbury@aeiveos.wa.com)
Date: Sat Feb 05 2000 - 10:51:50 MST
On Sat, 5 Feb 2000, Robin Hanson wrote:
>
> Since you mention AIDS, I'll mention that AIDS may have been caused by
> developing polio vaccine from chimp livers (see Hooper's book
> The River.)
Robin, I think you should asterisk the *may*. You may want to look at
"AIDS as Zoonosis: Scientific and Public Health Implications"
Science, 28 Jan 2000, pg 607;
Subscriber URL: http://www.sciencemag.org/cgi/content/abstract/287/5453/607
It seems pretty clear that HIV-1 and HIV-2 have different evolutionary
histories. While you may make a case that HIV-1 may have come from
chimpanzees, it looks like HIV-2 came from Sykes' monkey or Mangabeys.
There is also some lurking evidence that some cases of small cell
lung carcinoma may be attributed to SV40 viruses that may have been
present in early polio vaccines. So there are lots of "smoking guns"
with regard species crossovers that may have been helped by the
development of early vaccines.
>
> Here are the questions to ask:
> 1) How much have vaccines contributed to health?
While HIV may be the scourge now, clearly in the '50's Polio was
something that caused a great deal of harm. A brief glance at
Fields Virology indicates that in the early '50's, Polio was paralyzing
10-30,000 people a year. Now, if you can make a *strong* case for
Chimp-to-Human transmission for HIV-1 *and* a strong case that it was
derived from medical practices and did not occur (perhaps simultaneously)
with chimpanzee preparation or consumption as food, then you
could make an argument that this was bad simply on the basis
of loss of life to HIV vs. loss of life to polio. To be fairly
ruthless about it you would have to do an economic analysis on
the NPV of the human lives lost or severely devalued from the '50's
to '90s (Polio, had no vaccine been developed) vs. the '80's & '90's
(AIDS). Medical people often use Years of Potential Life Lost, and in
this case Polio might be considered worse from the perspective that it
generally affected younger people. I would guess the costs
(Polio vs. HIV) come out relatively speaking in the same ballpark.
> 2) How much have great apes contributed to vaccines, over and above
> what could have been done with other animals?
Also from Field's Virology it seems that the polio virus does not cause
pathology in mice, only in monkeys and humans. So it is an open
question whether you could have used anything but primates to develop
a polio vaccine. Given the costs involved, I suspect researchers only
use primates when there are no other good alternatives.
>
> The answer to the first question seems to be: suprisingly low.
Well, the cases for Polio, Measles, DPT, Tetnus, etc. vaccines
seems pretty clear to me. I think anti-Cancer vaccines will
demonstrate this even further in the future. I think you can
attribute modern health to three things: (1) sanitation,
(2) antibiotics, and (3) vaccines. Now exactly how much weight
you want to put on each of those may largely depend on your
local environment. People in cities need sanitation, people
in more rural areas probably benefit more directly from antibiotics
(curing infections). Vaccines probably benefit both but perhaps
to a lesser degree. A fourth factor is the simple understanding
of germ theory and communicability and getting medical practicioners
to follow practices that minimized transmission. But these factors
combined are what has extended average longevity from ~30-40 years
to ~75 years.
> I suspect the answer to the second question has a similar answer.
Hmmmmm.... Developing vaccines in animals that have different
biochemistries or do not exhibit pathologies is very difficult.
While HIV is inherently difficult due to its mutating nature,
it is also difficult because its pathology is worst in humans.
As viruses tend to attenuate in their hosts over time, you will
only get really bad effects in recent species crossovers. In
distant species a virus be able to be infectious or may be relatively
harmless. That makes it difficult to develop either drugs or vaccines
unless you use either the natural hosts or the species in which the
pathologies can be measured.
Robert
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