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COVID-19 Vaccine Mandates for Ontario’s Hospital Workers: Response to the Premier of Ontario

Version 1.0 | https://doi.org/10.47326/ocsat.2021.02.49.1.0

22,377 views | 1,321 downloads | Published: October 19, 2021

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Dear Premier Ford,

Thank you for the opportunity to share scientific evidence in response to your questions about COVID-19 vaccine mandates for Ontario’s hospital workers. In our response we consider hospital workers to include frontline healthcare workers and all other hospital employees, contractors, students, and volunteers, whose work is essential to the function of our province’s hospitals.

We have kept three things in mind when writing this letter. First, we want to emphasize the importance of protecting vulnerable patients from SARS-CoV-2 infections in hospital settings. Second, we want to ensure hospitals can continue to function with minimal disruptions due to staffing shortages associated with the impact of COVID-19. Finally, and importantly, we want to protect the health, safety, and wellbeing of all those working in our hospitals. Hospital workers have been the backbone of the province’s response to COVID-19 and have been there for Ontarians during this public health crisis. Requiring that healthcare workers be vaccinated against certain communicable diseases is evidence-based and protects the public. We trust the following helps you make an evidence-based decision regarding vaccine mandates in hospitals. 

There is now conclusive evidence that COVID-19 vaccines are highly effective and safe. Data from Ontario show that a fully vaccinated individual has a more than 80% reduction in the risk of catching COVID-19 and a more than 97% reduction in the risk of serious illness due to COVID-19. As a result of this reduced likelihood of becoming infected, fully vaccinated individuals have a lower probability of contributing to ongoing transmission of the virus, and if infected, appear to be infectious for a shorter period of time compared to the unvaccinated. Over 6 billion doses of COVID-19 vaccines have been administered around the world (more than 57 million doses in Canada) with careful monitoring for potential adverse effects. It is clear that the risks of serious side effects from vaccines are vanishingly low. COVID-19 vaccines are safe and effective. 

COVID-19 can spread to workers and vulnerable patients in hospitals and other healthcare settings. Data from Public Health Ontario demonstrate that a substantial number of COVID-19 cases originate inside hospitals. Infection prevention and control efforts by hospitals to reduce the spread of COVID-19 will likely help diminish the risk of transmission, but they are not perfect and require constant vigilance. Vaccines, in contrast, provide consistent and ongoing protection to both healthcare workers and patients. 


There are over ten million Ontarians, more than 83% of those eligible, who are fully vaccinated against COVID-19. However, that leaves several million Ontarians who are still not vaccinated and remain susceptible to SARS-CoV-2 infections and serious COVID-19 disease. This includes young children who are not yet eligible for vaccination. Patients in Ontario’s hospitals are more likely to be elderly and/or immunocompromised. These groups are at greater risk of SARS-CoV-2 breakthrough infections and severe COVID-19 disease, even when fully vaccinated. A fully vaccinated workforce reduces the risk of transmission to both unvaccinated and vulnerable fully vaccinated patients.

As you have noted, healthcare worker shortages are a serious risk to the ability of our hospitals to care for their patients.  Hospital workers who remain unvaccinated are at greater risk of being unable to work due to COVID-19. Both an acute SARS-CoV-2 infection and long-COVID can result in the need for significant time off work and, potentially, long-term disability. SARS-CoV-2 infection therefore poses a real and serious threat to the health of the hospital workforce. There is already significant fatigue and burnout among hospital healthcare workers. They will be further strained and at risk for burnout if their unvaccinated colleagues are unable to work due to COVID-19 infection. 

In contrast, early media reports from Ontario and data from the United States and globally suggests that across a range of hospital settings, the number of healthcare workers who actually leave the workforce to avoid vaccination is small. 

Vaccine mandates for healthcare workers are not new. Mandates for influenza vaccines for healthcare workers in high-risk settings, such as hospitals and long-term care homes, have been in effect across Canada and the United States for more than two decades. Studies of influenza vaccination mandates demonstrate that these policies can increase vaccine uptake. During the 2019-2020 influenza season, vaccine uptake among long-term care workers in the United States was approximately 70%, however, in settings with mandates, more than 85% of workers were vaccinated. Emerging evidence from long-term care settings suggests that mandates for COVID-19 vaccination increase uptake among staff. 

Surveys of healthcare workers’ attitudes towards COVID-19 vaccines show lower vaccine acceptance among those who are racialized, rural and have experienced discrimination. Trust-building strategies to increase uptake are important to counter equity and ethical concerns for hospital workers. These strategies include ongoing, multifaceted efforts such as education, personalized outreach and engagement by trusted leaders. These efforts can counter hesitancy, build confidence and trust, increase vaccine uptake and avoid losing valuable members of the workforce. 

A requirement for all hospital workers to be vaccinated against COVID-19, and to join with the majority of their colleagues and eligible Ontarians who have already been fully vaccinated, can enhance safety and reduce the risk of staffing disruptions due to COVID-19. COVID-19 vaccines help to protect the people working in Ontario’s hospitals, as well as the unvaccinated and vulnerable patients more at risk of SARS-CoV-2 infections and COVID-19 complications. Requiring that hospital workers be vaccinated is an evidence-based policy that protects Ontarians. 

Ontario COVID-19 Science Advisory Table

Document Information

In their role as civil servants at the Ontario Ministry of Health, Anne Hayes, Michael Hillmer, Fiona Kouyoumdjian, and David McKeown of the Ontario COVID-19 Science Advisory Table have recused themselves from this response to the Premier of Ontario.

Declarations of Interest: The declarations of interest of the members of the Ontario COVID-19 Science Advisory Table, its Working Groups, or its partners can be found at https://covid19-sciencetable.ca/. The declarations of interest of external authors can be found under Additional Resources.

Copyright: 2021 Ontario COVID-19 Science Advisory Table. This is an open access document distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided that the original work is properly cited.