How vaccines work

How vaccines work

How Vaccines Work on Youtube.

Video courtesy of Health Canada. All contents may not be reproduced without permission and are copyright of Her Majesty the Queen in Right of Canada, Represented by the Minister of Health, 2012.

How immunization works: A soccer mom's guide

Vaccines provide immunity that protects you from disease without the risk of the infection.  

Here's how vaccines work:

  • Vaccines contain a small amount of the germs or parts of the germs that cause disease. The germs in vaccines are either killed or weakened so they can't make you sick.
  • When you receive a vaccine, your body thinks the small amount of the disease germ is the disease itself, and your immune system starts creating antibodies (proteins that destroy disease germs).
  • The antibodies destroy the vaccine germs just as they would the disease germs (like a training exercise).
  • These antibodies stay with you for a long time and remember how to fight off the germ. If the real disease (not the vaccine) enters your body in the future, the antibodies are ready to fight it off before it has a chance to make you sick.
  • Often, your body remembers how to fight a germ for the rest of your life. However, sometimes you need a booster dose of a vaccine to remind your body how to fight off certain germs.

It's just like... A dress rehearsal for your immune system so it is prepared for the ‘real show’ (the disease). 

Sometimes vaccines prevent one disease. Sometimes they are combined to protect you from several diseases with one shot. For example, the MMR vaccine provides protection against measles, mumps and rubella.

Most vaccines need more than one dose over time to produce full protection. That’s why it’s important to follow the immunization schedule - it gives the best protection with the fewest doses of each vaccine.