Facts and fictions

Over the years, myths and misunderstandings have surrounded vaccines. Here are a few you should know the truth about:

Fiction: Vaccines can cause serious side effects

Serious side effects occur very rarely -- in less than one of every million vaccinations. Most side effects are usually very minor and temporary (a mild fever or sore arm, for example). In fact, no long-term effects have been associated with any vaccine currently in use, and every vaccine in Canada is thoroughly tested to meet strict health and safety requirements.

Fiction: Vaccines can cause autism

Developmental disorders like autism first become noticeable around the same age as a child's first immunization, leading some people to believe that the vaccination is causing these disorders. Countless studies have been conducted -- including many by Canada's National Advisory Committee on Immunization (which includes experts in the fields of pediatrics, infectious diseases, immunology, medical microbiology, internal medicine and public health) -- with each study finding no link between vaccinations and autism. Scientists have looked especially closely at thimerosal, a preservative containing mercury that is used in the influenza vaccine, and have found that thimerosal does not cause autism.

Fiction: These diseases are so rare, there is no need for my child to be immunized

While vaccines have drastically reduced the cases of many diseases in Canada, those diseases are still quite common in other parts of the world. Families that travel, and travellers from other countries, can unknowingly bring these diseases into Canada. If we're not all immunized, these diseases could quickly spread.

Fiction: "Nosodes" Offer the Same Protection as Vaccines

Homeopathic medicines, including Nosodes, are not vaccines. Health Canada has not licensed any homeopathic medicines for the purpose of providing immunity to a communicable disease. Vaccinating yourself and your children continues to be the most effective way to prevent and control vaccine-preventable diseases.

Fiction: Immunizing against multiple diseases can overload the immune system

Many clinics provide vaccines that immunize against several diseases at once (for example, the mumps, measles and rubella). This is practical for two reasons: First, it provides better protection against more diseases; second, the entire process is easier on children because fewer needles are used, and it's easier on parents because it cuts down the cost and number of doctors' visits. Extensive testing makes sure these 'combination vaccines' are safe. To receive a licence to combine vaccines, manufacturers must prove that the combination process does not make any of the individual vaccine components less effective.

Fiction: Many people who are immunized still get the disease; this proves that vaccines don't work

No vaccine is 100% effective. Because every person is different, about 10-15% of people vaccinated may not develop immunity to the disease. But think of the alternative: if nobody is immunized, everyone is vulnerable to the disease.

Fiction: Vaccines can transmit animal diseases to people

Animal cells are sometimes used to make vaccines, but this process is strictly controlled so that people aren't at risk. The vaccines are purified and each batch is tested to make sure it is free from infectious material.