Immunization protects people against diseases.

What is immunization?

Immunization is the process of giving a vaccine to a person to protect them against disease. Immunity (protection) by immunization is similar to the immunity a person would get from disease, but instead of getting the disease you get a vaccine. This is what makes vaccines such powerful medicine. Most vaccines are given by needle (injection) but some are given by mouth (orally) or sprayed into the nose (nasally). Immunizations are also called vaccinations, needles, shots or jabs.

How do vaccines work?

Vaccines contain the same germ that causes disease. But the germs in the vaccine have been killed or weakened so that they do not make you sick. Some vaccines contain only a part of the germ that causes disease.

When you get immunized, your body is tricked into thinking that it has been infected with the disease. It makes antibodies that kill the germs. These antibodies stay in your body for a long time and remember how to fight the germ. If the germs from the disease enter your body in the future, the antibodies destroy the germs before you can become sick. It is much safer to get a vaccine than the disease.  

Most people are fully protected against the disease after getting immunized. In rare cases, people who are immunized can still get the disease because they only get partial protection from the vaccine. This is more common in people with medical conditions that affect the immune system. Although these people may still get the disease, they will most likely get a milder sickness and not suffer serious complications. 

Find out more about vaccines and how they work.

What is herd immunity (community immunity)?

When enough people in a community are immunized against a disease, the chance of an outbreak is greatly reduced. This type of community protection is known as ‘herd’ or ‘community’ immunity. To reach herd immunity against a disease, a community must have between 74 to 95 per cent of the people immunized depending upon the disease.

Watch a video on herd immunity:

More stories

Hear real stories of people who were infected with vaccine preventable diseases:


Sherry’s story about meningitis

Sherry tells her story about how she lost her son to meningitis.

I lost my friend to meningitis

It only took four days for meningitis to take Leo's life. In B.C., Canada, grade 9 students will be offered a vaccine that prevents deaths like Leo's. Learn more.

Pertussis (whopping cough)

Jane’s story about whopping cough

Hear Janice tell her story about how her son contracted whooping cough.


Nathan's story about chickenpox

Many people are unaware of how serious chickenpox can actually be. Hear Nathan's story from his Mom about the stroke he suffered after becoming infected with chickenpox disease.

Haemophilus influenzae type b (Hib)

Marijean's story of haemophilus influenzae type b

Human papillomavirus (HPV)

HPV: Our family’s story

Audra and her aunt Laura are strong believers in the HPV vaccine, for good reason: Gisel, Audra's mother and Laura's older sister, died from cervical cancer at only 38.


Jenette's story about polio


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