There are more cases of multiple sclerosis (MS) today than 30 or more years ago. The reasons for this increase are earlier and improved methods of diagnosis, improved treatment, and longer survival of MS patients. The cause of MS is not yet known. There is some evidence suggesting that infection in childhood might play a role in the development of MS. There is no evidence that immunization causes MS. The cause of chronic fatigue syndrome is not known. Some opponents of vaccination have alleged that hepatitis B vaccination causes this illness. However studies comparing vaccinated and unvaccinated adults failed to show any increased risk of chronic fatigue syndrome after vaccination. There are many other conditions for which causes are not yet known, such as rheumatoid arthritis, Crohn's disease, ulcerative colitis and lupus erythematosus (SLE). Since most persons with these disorders were vaccinated in childhood, it is easy to blame the vaccine when no other cause can be found. However, there is no evidence to prove that these conditions are caused by vaccination. One recent study in England claimed that Crohn's disease (a chronic inflammation of the small intestines of unknown causes) was more common in young adults who had received measles vaccine than in unvaccinated adults. However, the methods used in this study had serious flaws, making it difficult to accept the study's conclusions. Moreover, two other laboratories have failed to confirm the study's finding that measles virus is present in samples of inflamed tissue from patients with Crohn's disease.

This document was published by the Canadian Paediatric society, 1997.

Posted by the Canadian Paediatric Society, July 1997.

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