Vaccine Safety


Girl receiving infection

The safety of vaccines is carefully monitored, starting early in the product development and continuing for as long as the vaccine is being used. Find out about what is done before and after vaccines are approved for use and what is known about the benefits and safety of specific vaccines.

There is a lot of false information about vaccine safety on the Internet. This can be confusing. Discover the answers to common questions and concerns about vaccines.


Safety Key Messages

Public Health Agency of Canada, Vaccine Safety Key Messages

Common reactions to vaccine(s) are mild and may include:

  • redness
  • itching and/or rash at the injection site
  • headache or dizziness (less common)
  • nausea


Severe allergic reactions are very rare. The dangers of vaccine-preventable diseases are many times worse than the risks of a serious reaction to the vaccine.


Get medical attention immediately if you develop any of the following symptoms within 3 days of getting the needle:

  • hives
  • swelling of the mouth and throat
  • trouble breathing, hoarseness or wheezing
  • high fever (over 40⁰C/104⁰F)
  • convulsions or seizures
  • or any other serious reaction to the vaccine

AEFI Factsheet


Immunize Canada

Immunize Canada Site

Immunize Canada- Vaccine Safety

  • The vaccines used in Canada are highly effective and extremely safe.
  • Health authorities worldwide take vaccine safety very seriously.  Expert committees in Canada investigate reports of serious adverse events.


Concerns? Questions?

If you have questions or concerns, talk to your doctor or nurse practitioner or call to speak to a vaccine team nurse at 519-376-9420 ext.

Or email us at


More Information

Immunization Information on the Internet


Vaccines: Busting Common Myths


Institute for Vaccine Safety

An independent assessment of vaccines and vaccine safety to help guide decision makers and educate physicians, the public and the media about key issues surrounding the safety of vaccines.


You might also like Diseases and Immunizations



Share this page