Study: Vaccines Don't Cause Arthritis, Other Diseases

Large scientific studies do not support claims that vaccines may cause diseases such as chronic arthritis, asthma, multiple sclerosis and diabetes, according to a study reported in the March issue of Pediatrics.

"Such reports have led some parents to delay or withhold vaccinations for their children," said study author Dr. Paul Offit. "This is very unfortunate, because the best available scientific evidence does not support the idea that vaccines cause chronic diseases."

Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia, and his colleagues reached their conclusion after reviewing current research on associations between vaccines and these diseases. They found that reducing vaccination rates actually leads to increases in preventable infectious diseases.

Offit discounted the hypothesis of molecular mimicry in which vaccines are suspected of causing autoimmune diseases such as arthritis, multiple sclerosis or type 1 diabetes by inadvertently stimulating the immune system to attack itself.

This hypothesis is based on the fact that some proteins on invading microbes are similar to human proteins, according to Offit. 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, Offit said 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."

Other sources: Children's Hospital of Philadelphia