Success of Vaccines Worldwide and in Canada
April 29, 2025
Written By Hanna Dada, Health Resource Navigator
Vaccines save lives, and with vaccines we have been able to eradicate and eliminate diseases reducing mortality and morbidity.
What is the difference between eradicating and eliminating a disease and what does it mean for modern vaccination?
By definition, the eradication of a disease is the “permanent reduction to zero of the worldwide incidence of infection caused by a specific agent.”i This involves eliminating all aspects of a disease, so it is no longer present anywhere. In that situation intervention measures are no longer required. On the other hand, disease elimination is more common. It does not require a permanent and global reduction in disease incidence; rather, it achieves restrictions on a defined geographic area. With this, measures to prevent the re-emergence or transmission of the virus like vaccines are still required.
Eradicated Diseases
Smallpox: Smallpox is a highly contagious ancient disease that induced epidemics throughout human history. People with smallpox were said to experience intense fever and progressive pustular rash that might leave large permanent scars. Overall, smallpox infected about 300 million people in the 20th century. Through vaccination, this has become the only human disease successfully eradicated in global health history, with the WHO making it official in 1980. Since 1977, no cases of smallpox have been reported again.
Poliomyelitis (polio): Polio is a highly infectious viral disease that largely affects children under 5 years of age. Wild poliovirus cases have decreased by over 99% since 1988, from an estimated 350,000 cases in more than 125 endemic countries to 6 reported cases in 2021. Of the 3 strains of wild poliovirus (type 1, type 2 and type 3), wild poliovirus type 2 was eradicated in 1999, and wild poliovirus type 3 was eradicated in 2020. As of 2022, the endemic wild poliovirus type 1 remains in two countries: Pakistan and Afghanistan.
Eliminated Diseases
Mumps: Caused by the rubulavirus, this results in low-grade fever, respiratory problems, and inflammation of the salivary glands. While highly infectious without a cure, vaccines have helped lower the cases by 99% since its introduction in 1967.
Measles: Measles is a highly contagious viral disease that can lead to serious complications for young children, including blindness, diarrhea, pneumonia, and encephalitis. Safe, effective, and inexpensive vaccines have been made available since the 1960s. While measles is still common worldwide, it has greatly decreased by 73% between 2000 and 2018.
Other diseases are on the way to elimination like Tetanus, Chickenpox, Malaria and Hepatitis B.
In Canada
| Comparison of case count for 6 vaccine-preventable diseases before and after introducing each vaccine | |||
| Disease | Case pre vaccine | Average annual cases 2016-2020 | Decrease |
| Whooping Cough (Pertussis) | 17,777 | 2,340 | 87% |
| Mumps | 36,101 | 737 | 98% |
| Measles | 53,584 | 37 | More than 99% |
| Diphtheria | 8,142 | 5 | More than 99% |
| Rubella | 14,974 | 1 | More than 99% |
| Polio | 2,545 | 0 | 100% |
Definitions:
Cases then: Average number of cases reported annually in Canada during the:
- 5 years before routine vaccine use or
- closest possible 5 years where stable reporting was occurring
Cases now: Average number of cases reported annually in Canada from 2016 to 2020.