According to the World Health Organization (WHO), immunization "is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine. Vaccines stimulate the body's own immune system to protect the person against subsequent infection or disease."
While immunity can also be achieved through natural exposure to wild type virus, this comes at the risk of serious disease, hospitalization and potentially even death.
- It is estimated that 2 to 3 million deaths are prevented each year by current immunization programs and vaccines.
- The Public Health Agency of Canada (PHAC) credits immunization as saving more lives in the last 50 years than any other health measure.