A review of 20 studies has concluded that there is no link between vaccines and autism. The review, “Vaccines and Autism: A Tale of Shifting Hypotheses,” is published in the Feb. 15 issue of Clinical Infectious Diseases.
In an invited article (PDF), Jeffrey S. Gerber and Paul A. Offit, Division of Infectious Diseases, The Children’s Hospital of Philadelphia, report that:
“Twenty epidemiologic studies have shown that neither thimerosal nor MMR vaccine causes autism. These studies have been performed in several countries by many different investigators who have employed a multitude of epidemiologic and statistical methods. The large size of the studied populations has afforded a level of statistical power sufficient to detect even rare associations.”
The review looked at three common theories about how vaccines are linked to autism:
- the combination measles-mumps-rubella vaccine causes autism by damaging the intestinal lining, which allows the entrance of encephalopathic proteins
- thimerosal, an ethylmercury-containing preservative in some vaccines, is toxic to the central nervous system
- the simultaneous administration of multiple vaccines overwhelms or weakens the immune system
Offit says that fears about vaccines are pushing down immunization rates and having a real impact on public health. “Parents should realize that a choice not to get a vaccine is not a risk-free choice. It’s just a choice to take a different, and far more serious, risk.”