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36   Cheap Vaccine Can Be Costly
     The Washington Post, Sunday, March 19, 1967

     Use of Such Potent Drugs Should Be Viewed
        As Another Major Medical Procedure

     In this series of articles on the biology of viruses, and its
practical application to the public health, I have been placing
considerable stress on the gaps in our knowledge of viruses.  It
is not my intention to discourage important public health programs
like polio and measles vaccinations.  However, it is possible for
a vaccine that prevents a million cases of a major disease to cause
serious side effects in 10,000 people.

     Because these 10,000 might not have been among those who would
have come down with the main disease, medical research has a
responsibility to perfect its tools to a higher standard, even while
the best ones available are distributed as widely as possible.

     Where vaccination is legally compulsory, as it is against 
smallpox; or virtually so, as against polio, we can observe an
interesting question of social policy.  When a large fraction of
the population is already vaccinated, the chain of infection is
broken -- with great benefit to unvaccinated people as well.  If
one individual then refuses vaccination, he no longer exposes himself
to very great risk, but is exploiting his fellow citizens who have
taken the trouble to be immunized.

     Some individuals may have their own reasons to refuse to
participate in this kind of social insurance; and if so, it might
be perfectly reasonable to impose a special tax as an alternative
contribution to the general welfare.

     What are the important gaps in our knowledge of viruses?  Most
important, what happens to a live virus in the human body after it
is put there by the vaccination?  Infection with measles, for
example, usually confers lifelong protection, and this may imply
that some tissues remain permanently infected with the virus -- or
with some parts of its genetic machinery -- but this is only
speculation.

     The most important issue in the virulence of a strain of a virus
is its tissue specificity.  The terror of poliovirus is that wild
strains occasionally leave the gut, which they usually inhabit with
no notable harm to the host, and enter the central nervous system.
The tame strains used for Sabin vaccine have been selected empirically
for having lost this propensity to travel, but we know nothing about
the biochemical basis of the viruses' tastes for one tissue versus
another.

     We are in a very poor position to predict what might happen
to reawaken a virus's appetite for brain.  

     However, we are beginning to understand dimly some of the ways
in which virus genes interact with those of host cells, which is
obviously fundamental to eventual knowledge of these relationships.
We also know that viruses of different strains can interact with one
another and produce new stains.  This opens the possibility that
harmless stains could cross-breed and produce virulent progeny.
This kind of result is easily demonstrated in the laboratory.

     The conceptual tools to attack these problems come mainly
from basic research in molecular biology, much of it seemingly very
distant from problems of human disease.  For example, the major 
turning point in our modern understanding of viruses came from the
work of Dr. A. D. Hershey of Cold Spring Harbor, Long Island, N.Y.

     His work during the past 15 years on genetic exchange in
bacterial viruses, and on the role of nucleic acid as the actual agent
of infection, laid the groundwork of current manipulation of animal
viruses.  It is an outstanding example of cogent scientific insight
that has influenced every worker in the field, but is almost unknown
to the general public.

     Although we should be avidly seeking new knowledge, there is a 
great deal we do know that is not now applied in practical vaccine
production.  We know how to purify viruses as chemical entities;
but most vaccines are crude products harvested directly from infected
cultures.  For example, there is no regulation that a vaccine be 
examined under an electron microscope for uniformity of its virus
particles, or that it be analyzed for its nucleic acid composition
or for the molecular weight of its particles.  The routine application
of similar techniques would have led to a much earlier detection of
the SV-40 contamination of polio vaccines.

     Cost is the main excuse for neglect.  But cheap vaccines may
result in the most horrendous catastrophes.  Vaccines are probably
the most potent drugs we expose ourselves to.  They can convey
enormous benefits, but if we are to get the most out of them we must
regard each vaccination with the same rigor as any other major medical
procedure.  We can hardly afford not to.

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