The risks associated with vaccines are infinitely less than the risks associated with the diseases themselves. Fever can occur after vaccination and may cause convulsions in a few cases. But fever-induced convulsions do not cause permanent brain damage and do not increase the risk of epilepsy or any other brain disorder. The risk of convulsions is much higher after natural measles or pertussis disease than after vaccination. Pertussis. Pertussis kills 1 to 3 infants every year in Canada and an equal number suffer severe brain damage. Brain damage after pertussis vaccine is extremely rare, if it occurs at all. Measles. Measles causes encephalitis (inflammation of the brain) in about 1 out of 1,000 cases. One-third of those with measles encephalitis die and one-third survive with brain damage. Encephalitis occurs about once in every one million measles vaccinations. This occurrence rate is so low that it is unclear whether the vaccine or some other infection is responsible. Mumps. Meningitis occurs in 1 in 10 cases of mumps. Meningitis occurs after 1 in 800,000 mumps vaccinations. Rubella. If a woman becomes infected during the first 20 weeks of pregnancy, chances are high (8 out of 10) that the fetus will also be infected. Joint pain affects twice as many women with natural infection as women who are vaccinated.

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

Posted by the Canadian Paediatric Society, July 1997.

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