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http://www.eurekalert.org/pub_releases/2003-03/chop-dvc030303.php
“It is not unfair to conclude that medicine is the only branch of science
that has based its structure on opinions and suppositions rather than on laws
and principles.”
—George Vithoulkas, “The Science of Homoeopathy”.
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Do vaccines cause asthma, allergies or other chronic diseases?
Reviews of scientific data uphold vaccine safety
Philadelphia, Pa—Large scientific studies do not support claims that vaccines
may cause chronic diseases such as asthma, multiple sclerosis, chronic arthritis
and diabetes, according to a report in the March 2003 issue of Pediatrics. The
report’s lead author, Paul A. Offit, M.D.., chief of Infectious Diseases and
director of the Vaccine Education Center at The Children’s Hospital of
Philadelphia, identifies flaws in proposed biological explanations for how
vaccines cause chronic diseases and reviews current research on associations
between vaccines and those diseases.
“Anecdotal reports and uncontrolled studies have proposed that vaccines may
cause particular allergic or autoimmune diseases,” says Dr. Offit. “Such reports
have led some parents to delay or withhold vaccinations for their children. This
is very unfortunate, because the best available scientific evidence does not
support the idea that vaccines cause chronic diseases. Scientific studies have
shown, however, that reducing vaccination rates lead to increases in preventable
infectious diseases.”
In the article, co-authored by Charles J. Hackett, Ph.D., of the National
Institutes of Allergy and Infectious Diseases, Dr. Offit critically analyzes
proposed explanations for a link between vaccines and chronic diseases, such as
the “hygiene hypothesis.” The hygiene hypothesis states that improved hygiene
and decreased early exposure to common childhood infections may actually raise a
child’s risk of developing allergies. Several studies support this hypothesis,
says Dr. Offit, such as findings that children who attend childcare or live in
large families are less likely to have allergies.
However, adds Dr. Offit, the hygiene hypothesis does not fit vaccine-related
diseases. Vaccines do not prevent most common childhood infections, such as
upper and lower respiratory tract infections, that form the basis of the hygiene
hypothesis. On the other hand, vaccine-preventable infectious diseases such as
measles, mumps and whooping cough are easily transmitted regardless of home
hygiene. “The flaws in using this biological mechanism to explain a link between
vaccines and allergies are consistent with large-scale epidemiological studies,”
said Dr. Offit. “Those studies found no evidence that vaccines increase the risk
of asthma, food allergies or other allergic disorders.”
Another set of hypotheses proposes that vaccines cause autoimmune diseases such
as multiple sclerosis or type 1 diabetes by inadvertently stimulating the immune
system to attack itself. The mechanism of “molecular mimicry” is based on the
fact that some proteins on invading microbes are similar to human proteins. In
responding to proteins from the infectious agent, the immune system may
mistakenly attack similar proteins in the patient’s body, and set off a disease.
Molecular mimicry may indeed allow a natural infection to trigger an autoimmune
disease, as when Lyme disease leads to chronic arthritis. However, says Dr.
Offit, this process cannot be extended to what happens with vaccines. Naturally
occurring viruses and bacteria are much better adapted to growing in humans than
vaccines, and are much more likely to stimulate potentially damaging autoimmune
reactions.
“Vaccines are engineered to carry weakened or deactivated pathogens, and
consequently there are critical differences between natural infection and
immunization,” said Dr. Offit. “These differences are reflected in the many
well-controlled epidemiological studies that do not show a causal relationship
between vaccines and autoimmune diseases, including multiple sclerosis, type 1
diabetes and chronic arthritis.”
About the Expert:
Paul A. Offit, M.D., is the director of the Vaccine Education Center and chief
of Infectious Diseases at The Children’s Hospital of Philadelphia. An
internationally recognized expert in virology, immunology and vaccine safety, he
is a member of the Advisory Committee on Immunization Practices to the Centers
for Disease Control and Prevention. In addition to publishing more than 90
peer-reviewed scientific papers, Dr. Offit is co-author of the book “Vaccines:
What Every Parent Should Know.” He frequently lectures to national and
international healthcare organizations about vaccine safety and efficacy.
Under the direction of Dr. Offit, The Children’s Hospital of Philadelphia
established The Vaccine Education Center in October 2000 to respond to the
rapidly growing need for accurate, up-to-date, science-based information about
vaccines and the diseases they prevent. The Center is a nationally recognized
educational resource for healthcare professionals and parents, providing
information on the full spectrum of vaccine-related topics. Approximately 400
people per day visit the Center’s comprehensive Web site (vaccine.chop.edu).
Founded in 1855 as the nation’s first pediatric hospital, The Children’s
Hospital of Philadelphia is ranked today as the best pediatric hospital in the
nation by a comprehensive Child magazine survey. Through its long-standing
commitment to providing exceptional patient care, training new generations of
pediatric healthcare professionals and pioneering major research initiatives,
Children’s Hospital has fostered many discoveries that have benefited children
worldwide. Its pediatric research program is among the largest in the country,
ranking second in National Institutes of Health funding. In addition, its unique
family-centered care and public service programs have brought the 381-bed
hospital recognition as a leading advocate for children and adolescents from
before birth through age 19. Children’s Hospital operates the largest pediatric
healthcare system in the U.S. with more than 40 locations in Pennsylvania, New
Jersey and Delaware.
ALL INFORMATION, DATA, AND
MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR GENERAL INFORMATION
PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE KNOWLEDGE OR OPINIONS
OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED AS PROVIDING MEDICAL OR
LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND
COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN CONSULTATION WITH
YOUR HEALTH CARE PROVIDER.