From: x91miley@gw.wmich.edu
Newsgroups: rec.food.veg
Subject: polio
Date: 27 Jan 93 22:25:28 EST
Organization: Western Michigan University

Here's some information on polio vaccine development.

POLIO AND ANIMAL EXPERIMENTATION

     Although Polio has afflicted humans for thousands of years (cases have
been reported as far back as ancient Egypt), not until the mid-nineteenth
century was polio recognized as an infections disease with a specific cause.

     A Swedish epidemiologist, Wickman, established that polio was highly
contagious even when paralysis or other symptoms were not present.  He also
identified the means of transmission and discovered that symptoms such as
central nervous system dysfunction are not always evident in afflicted persons;
most infected people's nervous system is not involved at all.  In 1908, the 
poliovirus was isolated and injected into two rhesus monkeys.  The enthusiasm
for experimental work soon killed widespread interest in Wickman's clinical
work.  This meant that it would take decades and many wrong turns for the
animal researchers to discover what Wickman had already established.  As John
R. Paul notes in his _History_of_Poliomyelitis_, "In the end, no amount of
experimentation on the monkeys could upset the fundamental clinical truths
that Wickman had discovered."

    The use of non-human primates in the search for a polio vaccine led to a
number of mistaken ideas.  Because of the work done with monkeys, researchers
believed that polio was predominantly a disease of the nervous system.
However, in humans, polio usually manifests as a gastrointestinal infection
with either mild, flu-like symptoms or no symptoms at all; only about one in a
hundred polio cases show neurological problems.

     Monkey research also led experimenters to believe that polio was
transmitted through the air, into the nose, and directly to the central nervous
system.  Human clinical cases, on the other hand, demonstrated that polio
enters the body through ingestion, grows in lymph nodes, and then may spread
through the blood stream to the nerves.

     The findings with monkeys also led to inappropriate and/or dangerous 
treatment methods.  In 1937, a zinc sulfate nasal spray was used to control the
polio epidemic in Toronto; it did not work.  In addition, humans are often 
allergic to the tissues of other species--vaccines grown in other animals can 
cause anything from mild local reactions, to severe illness and even death.

* The Real Breakthrough

     In 1948, three American researchers, Enders, Weller, and Robbins, proved
that the poliovirus would grow in human non-nervous tissue cultures.  They had
previously attempted to grow the virus on mouse intestinal tissue cultures, but
failed.  Growing the virus in human tissues lead to two major breakthroughs;
first, it set aside the mistake belief, based upon monkey research, that polio
was simply a nervous system infection.  Second, it provided a steady source of
pure virus for vaccine production.  This discovery won the team the 1954 Nobel
Prize for Physiology and Medicine.

* The Vaccines

     Six years later, a vaccine for polio was developed.  In 1953, Jonas Salk
developed an injectable, killed virus vaccine and, two years later, Albert
Sabin developed a weakened, oral live-virus vaccine,  Monkey tests are still
used to check the safety of the vaccine batches, although the World Health
Organization has consistently recommended that the Monkey Safety Tests for the
Salk vaccine be dropped in favor of an _in vitro_ test.

     While the Sabin vaccine is, in theory, more effective because it follows
the natural path of infection, it has a tendency to cause polio in one out of
every 350,000 people inoculated.  The Salk vaccine, because it employs a killed
virus, has a zero chance of infecting a recipient.  Due to the resultant
liability, the Sabin vaccine is now more expensive than the Salk vaccine.

     Testifying during a 1984 House subcommittee hearing, Sabin blamed delays
in the development of a vaccine to "an erroneous conception of the nature of
the human disease based on misleading experimental models of the disease in
monkeys."

References:

_Nova_ (#1510): "Can You Still Get Polio?" PBS, 5 April 1988.

Paul, John R., MD. _A History of Poliomyelitis_, New Haven, CT: Yale University
Press, 1971.

Radetsky, Peter, _The Invisible Invaders:_The Story of the Emerging Age of 
Viruses_, Boston: Little, Brown and Company, 1991.

Rowan, Andrew N. _Of Mice, Models, & Men:_A Critical Evaluation of Animal 
Research_, Albany, State University of New York Press, 1984.

Sabin, Albert, MD. Hearing before the Subcommittee on Hospitals and Health Care
of the Comittee on Veterans' Affairs, House of Representatives, Ninety-Eighth
Congress, Second Session, 26 April, 1984.

Sarros, Elaine, "The Story of Polio--And the Monkey Model." unpublished paper,
1990.


                             Physician's Committee for
                              Responsible Medicine
                                 P.O. Box 6322
                              Washington, DC 20015
                                 (202) 686-2210

-- 
Tim Miley, Western Michigan University computer science student.
                    x91miley@gw.wmich.edu

"Speculating upon their...constant fear of pain and disease,...[the medical
industry] has created the illusion that she wields mysterious and unlimited
powers...  So the peoples of the western hemisphere have prostrated
themselves..., imagining her as an almighty goddess...to whom common mortals may
not even raise their eyes, lest they be blinded.  But if they dared do so, they
would discover that their empress hasn't got a stitch on and is gruesome to
behold." Hans Ruesch, Slaughter of the Innocent.
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