|
Vaccine Safety > Issues of Interest > Cancer
Institute of
Medicine (IOM) Report
Immunization Safety Review:
SV40 Contamination of Polio Vaccine and Cancer
Released October 22, 2002
Contents of this page:
Related links/pages:
Overview of the IOM Report
Background
In 2000, the
Centers for Disease Control and Prevention (CDC) and the National
Institutes of Health (NIH) asked the Institute of Medicine (IOM)
to establish an independent expert committee to review hypotheses
about existing immunization safety concerns. To date, the committee
has released reports on the measles, mumps, rubella (MMR) vaccine
and autism; thimerosal-containing vaccines and neurodevelopmental
disorders; multiple immunizations and immune dysfunction; and, hepatitis
B and demyelinating neurological disorders.
Simian
virus 40, or SV40, was discovered in 1960. It occurs naturally in
some species of monkeys, though it does not typically cause symptoms
or illness except in cases where the animal has chronic problems
with its immune system. Soon after its discovery, SV40 was identified
in polio vaccine. At the time, rhesus monkey kidney cells, which
contain SV40 if the animal is infected, were used in preparing polio
vaccine. Once the contamination was recognized, steps were taken
to eliminate the virus from future vaccines. Interest in SV40 has
increased in the last several years because the virus was found
in certain forms of cancer in humans.
Conclusions
The IOM’s Immunization
Safety Review Committee found that the evidence is inadequate to
accept or reject a causal relationship between SV40-containing polio
vaccines and cancer. The committee also concluded that
- the biological evidence is strong
that SV40 is a “transforming” virus (able to transform
normal cells into malignant cells),
- the evidence is of moderate strength
that SV40 exposure could lead to cancer in humans under natural
conditions, and
- the evidence is of moderate strength
that SV40 exposure from polio vaccine is related to SV40 infection
in humans.
Recommendations
In light of the biological
evidence supporting the theory the SV40-contamination of polio vaccines
could contribute to human cancers, the committee recommends continued
public health attention in the form of policy analysis, communication,
and targeted biological research. These recommendations include
development of sensitive and specific blood tests for SV40 and a
vaccine contamination and prevention plan. The committee did not
recommend a review of the current use of polio vaccine on the basis
of concerns about cancer risks, because the vaccine used today is
free of SV40.
Next Steps
The committee has made
helpful recommendations about policy analysis, communication, and
biological research which are important to resolve outstanding issues
related to the hypothesis that SV40 contaminated polio vaccine causes
cancer. These recommendations will be considered in depth by Public
Health System agencies over the next several months.
Links
to actual IOM report
The IOM report and the
news release are available on the Web at
|
