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U of T’s health science deans address vaccination

March 3/2015

By: Howard Hu, Dean of the Dalla Lana School of Public Health and Trevor Young, Dean of the Faculty of Medicine, University of Toronto

As deans of two of the health sciences faculties at the University of Toronto, we teach our students that vaccines are safe, effective and vital to children’s health.  Vaccines are one of history’s most important and significant achievements in public health and medicine. The best evidence that science can provide proves that the health benefits of vaccines far outweigh their potential side effects, and we instruct our students accordingly.

Vaccination is a cornerstone of public health and medicine. Over the last 50 years, it has saved more lives than almost any other health measure. Vaccines are crucial to prevent devastating diseases, like measles, polio and pertussis (whooping cough).

Despite the scientific consensus and decades of advances in human health, there has been a remarkable rise of infectious diseases in the last year, some of which are vaccine-preventable. A rise in vaccine hesitancy and vaccine refusal has contributed to the resurgence of completely preventable diseases that pose a danger to our community.

According to Professor Denis Daneman, Chair of U of T Medicine’s Department of Paediatrics, “the development of vaccinations against common and potentially lethal diseases represents some of the most important advances in medicine over the past century. Some diseases such as small pox and polio have all but disappeared, the complications of measles and chicken pox prevented, and the scourge of childhood diarrhea markedly decreased with rota virus vaccination. Those families who are "vaccination-hesitant" need to be reassured of both the safety and effectiveness of the major vaccines. Vaccinating our most vulnerable, namely our children, is a vital social responsibility.”

Professor David Fisman, an epidemiologist in the Dalla Lana School of Public Health, lectures on herd immunity, or community immunity, which occurs when a critical portion of a community is immunized against a contagious disease. Accordingly to Fisman:

“Herd immunity is a product of public health. Because most members of the community are protected against that disease, there is little opportunity for an outbreak. This protects those who cannot be vaccinated, such as infants, pregnant women, or immunocompromised individuals. Herd immunity is why, ten years ago, there were no cases of measles in most of the Western world.  But because measles is so infectious, approximately 95 per cent of the population must be vaccinated to keep it from coming back.  A breakdown of herd immunity is why Canada, France and the UK have all seen reappearances of measles and mumps in recent years.”

In each of our faculties, we teach students to critically interpret data, consider the source and make an informed, evidence-based decision on the appropriate diagnosis, treatment or course of action. We train health professions who have a responsibility to protect the population from disease, and we take this role very seriously.

The problem is that despite all the clinical evidence and decades of advances in human health, many people continue to rely on anecdotal evidence and inaccurate information to make their decisions around vaccinations.  For some, a single, alarming story on social media is more compelling than the weight of scientific evidence compiled by the scientific community, which presents us educators with a new challenge.  Working with our students and the medical community, we will find ways to overcome vaccine hesitancy in patients.

We encourage you to speak to your health care provider if you have concerns about vaccination.

If you have any questions, please contact:

U of T Medicine:

Dalla Lana School of Public Health: