By Dr. Ana, Medical Affairs Lead, Primary Care & Hospital, at Pfizer Canada
During my time in medical school, a professor said, "There are two interventions that have had the biggest impact on public health: water purification and vaccines." I came to understand the truth of this statement after working in the vaccine field for over a decade. Vaccines often become overlooked because of their own success. Let me explain why.
The reason we do not see many vaccine-preventable diseases is due to the implementation of national or provincial immunization programs aiming for high vaccine coverage against several diseases. For example, in many countries, polio is no longer a concern, while in others, it remains a public health issue.
During my pediatric hospital rotation, I learned about past polio treatments. One was the iron lung, a large cylinder-shaped ventilator that helped patients breathe. Survivors often suffered muscle weakness and deformities. It made me think about how the introduction of polio vaccines has saved so many lives.[1]
Vaccines play a crucial role in helping to prevent and eradicate diseases. The best example of disease eradication is smallpox, a deadly disease most of us have never encountered. Did you know that about three out of ten people who became infected died? And those who survived lived with scars. After tremendous effort and many years of intensive immunization campaigns led by the World Health Organization, smallpox became the only vaccine-preventable disease that has been eradicated worldwide.[2]
Although most vaccine-preventable diseases have decreased dramatically, we need to continue striving to further reduce and, likely in the future, eradicate those that remain.
Vaccines' public health impact is underestimated because we no longer see certain of the diseases they prevent. When vaccination rates drop, diseases re-emerge, underscoring the need for continuous efforts.[3]
Measles outbreaks highlight this point; it is highly contagious, more so than COVID-19, influenza, or chickenpox, and can lead to severe complications like respiratory failure or brain injury. Long-term issues like blindness, deafness, or subacute sclerosing panencephalitis (SSPE) can also occur.[4]
In Canada, measles cases have been rare, thanks to high immunization coverage. However, due to increased measles activity globally, there has also been an increase in the number of cases in Canada, mainly in non-vaccinated populations or those with incomplete immunization schedules.
The outbreak in New Brunswick, which began on October 18, 2024, due to a travel-related case, has led to further cases in Ontario and Manitoba. Ontario has reported 816 measles cases (678 confirmed and 138 probable) as of April 9, 2025. Quebec has been dealing with measles cases since December 2024, reporting 40 confirmed cases of measles as of April 9, 2025.[5,6]
I could continue giving examples of well-known vaccine-preventable diseases such as influenza, RSV, and COVID-19. While COVID-19 fatigue exists everywhere, we must acknowledge that it is one of the best examples of a successful implementation of a vaccine program that allowed us to return to normalcy. RSV has also hampered the public health system in recent years with an increased number of hospitalizations.[7]
Vaccines have been crucial in combating diseases. Their success has led some to believe these diseases are no longer a threat, when in reality, high vaccination coverage is what keeps them at bay.
Continued support for immunization is essential to prevent the return of vaccine-preventable diseases.
I see this as a two-way call to action:
As a healthcare professional, be sure to recommend the vaccines best suited for your patients.
As an individual, ensure you understand the risks and benefits of vaccines by discussing them with your healthcare professional, especially if you have conditions such as chronic lung disease, diabetes, cardiovascular disease, or if you are immunocompromised. Consider staying up to date with recommended vaccines for your age, vaccinate your children, and inquire about vaccines during pregnancy for your and your baby's protection.
As we mark National Immunization Awareness Week, let's take this opportunity to acknowledge the critical role vaccines play in protecting our communities. By staying informed, getting vaccinated, and supporting immunization efforts, we contribute to a healthier future for everyone. Remember, vaccines have the potential to save lives.
[1] Garip Y, Eser F, Bodur H, Baskan B, Sivas F, Yilmaz O. Health related quality of life in Turkish polio survivors: impact of post-polio on the health related quality of life in terms of functional status, severity of pain, fatigue, and social, and emotional functioning. Rev Bras Reumatol Engl Ed. 2017 Jan-Feb;57(1):1-7. English, Portuguese. doi: 10.1016/j.rbre.2014.12.006. Epub 2015 Mar 10. PMID: 28137397.
[2] Centers for Disease Control and Prevention, History of smallpox, https://www.cdc.gov/smallpox/about/history.html, Accessed April 2, 2025.
[3] Lubanga AF, Bwanali AN, Kangoma M, Matola Y, Moyo C, Kaonga B, Ssebibubbu S, Makole TJ, Kambili F, Chumbi GD, Munthali L, Mwale A, Kaphesi F, Simfukwe R, Mphepo M, Kapatsa T, Harawa G, Mpinganjira SL. Addressing the re-emergence and resurgence of vaccine-preventable diseases in Africa: A health equity perspective. Hum Vaccin Immunother. 2024 Dec 31;20(1):2375081. doi: 10.1080/21645515.2024.2375081. Epub 2024 Jul 9. PMID: 38982713; PMCID: PMC11238914.
[4] UNICEF, How dangerous is Measles?, https://www.unicef.org/eca/stories/how-dangerous-measles, Accessed April 2, 2025.
[5] Gouvernement du Quebec, Measles Outbreak, https://www.quebec.ca/en/health/health-issues/a-z/measles/measles-outbreak, Accessed April 2, 2025.
[6] Public Health Ontario, Measles in Ontario, https://www.publichealthontario.ca/-/media/Documents/M/24/measles-ontario-epi-summary.pdf?sc_lang=en&rev=151281bd66344adaa501080d2389bb44&hash=66443467F410FBD2E71378196BEA72C1, Accessed April 15, 2025.
[7] Stephen Mac, Scott Shi, Brad Millson, Ali Tehrani, Masha Eberg, Varun Myageri, Joanne M. Langley, Scott Simpson, Burden of illness associated with Respiratory Syncytial Virus (RSV)-related hospitalizations among adults in Ontario, Canada: A retrospective population-based study, Vaccine, Volume 41, Issue 35, 2023, Pages 5141-5149.
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