How do we know vaccines are safe?

Question: 
How do we know vaccines are safe?
 
Answer: 
Only vaccines that are proven to be safe, effective, and of high quality are approved for use in Canada. 
 
Here are some important things to know about vaccine safety:
 
  • The approval process for vaccines is more stringent than most drugs available in Canada.
  • It can take up to ten years or longer for a vaccine to be developed, tested, and approved for use by Health Canada. Occasionally, the process can be expedited (happen more quickly) if there is an urgent need for a vaccine (for example, during a pandemic). No safety steps are skipped in these cases, and the vaccine still has to meet all the same safety requirements. An example is COVID-19 vaccines
  • Health Canada only approves a vaccine if it is safe, it works, it meets manufacturing standards, and the benefits outweigh the risks.
  • Because vaccines are given to healthy people, including children, they are held to the highest safety standard—even higher than most drugs used for treatment. 
  • Like any medicine or supplement (including vitamins), vaccines can cause side effects. Usually vaccine side effects are minor, such as a sore arm or mild fever, and go away quickly. Many people who receive vaccines have no side effects at all. Serious side effects are very rare. 
  • A vaccine’s safety is continuously monitored following its approval. 
  • Canada has several advanced systems in place (at the local, provincial, and national levels) to carefully monitor the safety of vaccines and detect any safety concerns. 
  • In the very rare event that a lot (batch) of vaccine results in an unexpected side effect, these systems can ensure that the rest of the lot is not used. 
 
Date last reviewed: 
Thursday, May 05, 2022