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35   Flaws in Disease Data
     The Washington Post, Sunday, March 12, 1967

     The virtual conquest of polio by immunization of most of the
population with the Salk and Sabin vaccines is a cardinal achievement
of public health.  Fifteen years ago, there were more than 50,000
cases of polio a year.  In 1964, there were only 121 cases reported
and most of those afflicted had not received the immunization.

     Yet for all its proved value, mass immunization has potential
dangers that need to be explored more fully.  We must improve our
techniques of collecting large-scale data on the safety and efficacy
of mass immunization programs.  Despite uncertainties, however, no
one should be deterred from seeking immunization against polio.  At
this point, the danger of polio greatly exceeds any danger likely
to be discovered by future research.

     The uncertainties exist nevertheless and it is the job of science
to remove them.  They were emphasized when a new virus, SV-40, was
discovered as a contaminant of seedstocks and production batches of
the polio vaccines.  SV-40 occurs in rhesus monkeys, whose tissues
are used for polio-virus cultivation.

     The virus has no obvious effect on the tissues of the monkeys,
but it has been discovered to cause tumors in hamsters injected with
it shortly after birth.  There has been no evidence that the same
results can be expected in humans, there has been no huge increase
in cancer since the polio immunization program began in 1955 and
there is no positive proof of any human diseases that can be
associated with SV-40.

     We must, however, ask how sensitive our surveys are.  How many
cases of a new disease would have to be associated with SV-40 before
we realized the relationship?

     Dr. M. R. Hilleman, virologist at the Merck Institute for
Therapeutic Research, who discovered SV-40 in 1960, wrote in 1964,
"Careful followup in persons who receive such vaccine has failed, to
date, to reveal any adverse effect attributable to the vaccine".

     He refers to a paper by Dr. J. F. Fraumeni Jr., and colleagues
at the National Cancer Institute, published in the American Medical
Association Journal Aug. 30, 1963.  The study appears to be the
main foundation of prevalent attitudes about SV-40.

     Dr. Fraumeni found that during the introduction of Salk vaccine,
batches used in different states contained varying levels of SV-40
contamination.  A study was made of mortality statistics compiled
in 1959 for children born in 1948 and who received the vaccine in
1955.  If SV-40 was associated with cancer, there should have been
a higher incidence in children living in states which received the
vaccine containing the greatest amount of SV-40.  But no significant
differences were found.

     As Dr. Fraumeni points out, however, a latent period of longer
than four years between inoculation and contraction of a disease
would have frustrated this research.  

     Now, it so happened that in 1952, three years BEFORE the
immunization began, the incidence of leukemia was 60 per cent higher
in the states that later proved to be areas of high exposure to
SV-40.  Any association between the two situations would be illogical
and obviously spurious, but nevertheless, under our present systems
of reporting diseases and with the crudeness of our vital statistics
procedures, such a connection would be possible.

     The higher incidence of leukemia in those areas can reasonably
be attributed to variations in diagnosis and reporting of disease.
That this conclusion is possible in itself gives some idea of the
poor precision that can be expected from present procedures.

     The sad fact is that there has been no large-scale followup of
specific individuals exposed to SV-40 because of the lack of adequate
records.  And now that SV-40 is a recognized potential contaminant,
it would be ethically questionable, and in fact it is currently
forbidden by government regulation, to administer Salk or Sabin
vaccine that is not proven to be free of SV-40.

     Unhappily, it would be quite possible for SV-40 to induce many
thousands of cases of childhood diseases, or, on the other hand, to
immunize against many others, all unbeknownst to anyone because of
the inadequacy of present investigative techniques.

     The only technique that would give us information of any real
value would be explicit registration of exposures to specific batches
of vaccines on a record that identifies each recipient for later
followup.

     This implies a much more meticulous and individual approach to
vaccination than we have been accustomed to and it certainly would
be more expensive.  So would other measures that must be elaborated
if we are to achieve the same assurance of safety and efficacy of
vaccines that we now demand from other drugs.

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