Vaccine Safety

Frequently Asked Questions

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I've heard that MMR can cause autism. Is that true?

Medical researchers and scientists around the world have studied information collected over many years to see whether there is a link between measles vaccine and autism, a lifelong developmental disorder. They have not found any evidence of a link.

Immunization is one of the best ways to protect children against disease. In Canada, children are vaccinated against many serious illnesses, including measles, mumps and rubella (German measles). The vaccines that Canadian children receive, including the MMR, are very safe.

Is measles dangerous?
Measles is a serious disease that can cause ear infection, pneumonia or even encephalitis (swelling of the brain). Before the vaccine was introduced in 1963, there were about 350,000 cases of measles each year in Canada. According to the Public Health Agency of Canada, there were 101 cases of measles reported in 2007.

Canadian authorities, including the Public Health Agency of Canada, Health Canada and the Canadian Paediatric Society, recommend that all children continue to receive the MMR vaccine at the appropriate time. Canadian children receive two doses of the MMR vaccine - the first at 12 months and the second at 18 months or before they start school, depending on where they live.

What is autism?
The symptoms of autism include problems with social interaction, behaviour and communication. Doctors don't know exactly what causes this developmental disorder.  The symptoms usually appear during the first three years of life - when most children are receiving their vaccines. The idea that the MMR vaccine is linked to autism began in 1998, when one study claimed that the measles vaccine could lead to the development of autism. The study, which involved a very small number of children, was flawed in many ways from a scientific point of view, and numerous studies on this topic since then have not found any evidence of such a link.

For more information:

• Vaccines and Autism
• Canadian Coalition for Immunization and Awareness Promotion web site
• Measles
• Autism
• Tracking Autism Spectrum Disorders in Canada

 

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