Autism And Vaccines: No Link Found
According to a review published in the February 15, 2009 issue of Clinical Infectious Diseases, studies linking autism to vaccines can be confusing. However, the majority of studies show there is no link between MMR vaccine, thimerosol in vaccines and autism. Nor do multiple vaccinations in childhood cause autism from a weakened immune system.
Study author Paul Offit, MD, of the Children's Hospital of Philadelphia, expresses concern about declining vaccination rates in children because one study contradicts another. He says, "When one hypothesis of how vaccines cause autism is refuted, another invariably springs up to take its place."
The current study looked at three major theories, showing that biological and epidemiologic studies disprove the link between autism and vaccines.
As parents refuse vaccination for their children, the threat to public health continues to increase. The most recent evidence involves the measles outbreak in California last year, and more recently the death of one child in Minnesota.
Dr. Offit and his colleagues reviewed more than a dozen large studies from five countries to find if there is any substantial evidence linking MMR vaccine to autism. They concluded the appearance of autism following MMR vaccine is nothing but coincidence because MMR vaccine is given at the same time autism usually manifests in children.
The researchers also reviewed seven studies from five countries. They found that thimerosol, used for fifty years in vaccines could not be linked to autism. Vaccines with or without thimerosol did not affect autism rates.
Finally, the current study addresses hypotheses that vaccine weakens the immune system in children, leading to autism. They conclude that there is so little material in the vaccines, that the result of childhood immunization could not weaken immunity and cause autism.
The researchers clearly cannot find a definite link between autism and childhood vaccines. They only find hypotheses when looking at available studies.
The researchers do not say childhood vaccines are completely risk free. Dr. Offit says not getting your child vaccinated is…"just a choice to take a different, and far more serious, risk."