Council of Chief Medical Officers of Health Statement on Implementing COVID-19 Vaccination in Canada

We recently marked the one-year anniversary of the global COVID-19 pandemic. Over the past year, people in Canada and across the world have mobilized to combat this virus and have collectively sacrificed a great deal.

The development of vaccines able to protect against severe COVID-19 outcomes has provided a new opportunity to protect ourselves, our families and communities, so all of us can return to a sense of normalcy. As Canada's Chief Medical Officers of Health, we are committed to implementing a vaccine strategy that brings the greatest benefit to our populations. The goal of Canada's COVID-19 immunization response is to enable as many people as possible to be immunized as quickly as possible against COVID-19 with a safe and effective vaccine, while ensuring that high-risk populations are prioritized. This strategy will contribute to the overall pandemic response goals of minimizing serious illness, death and societal disruption. It will be achieved by acting on evidence and public health principles, as well as through collaboration across our jurisdictions and with First Nations, Inuit and Metis partners.

With increasing supply of approved vaccines that are safe and effective against symptomatic COVID-19, we are now well-equipped to scale up vaccination and maximize protection of more individuals in Canada faster. We are doing this by first vaccinating populations at highest risk of severe health outcomes and COVID-19 exposure, and ensuring access to and uptake of COVID-19 vaccines for adults in communities that have been disproportionately affected by COVID-19 because of social and economic inequities.

As vaccination accelerates across the country, we continue to be guided by the expert advice of provincial immunization committees and the National Advisory Committee on Immunization (NACI). In light of accumulating real-world effectiveness evidence, NACI recommends that in the context of limited COVID-19 vaccine supply and the ongoing pandemic, jurisdictions should maximize the number of individuals benefiting from the first dose of vaccine by extending the timing of the second dose of COVID-19 vaccine dose up to four months after the first. Second doses should be offered as soon as possible after all eligible populations have been offered first doses, with priority given to those at highest risk of severe illness and death from COVID-19 disease. Provinces and Territories may choose to shorten the time between the first and second dose of a two-dose series for COVID-19 vaccines in specific populations based on their local epidemiology, vaccine supply and vaccine delivery mechanisms.

As Chief Medical Officers of Health, we welcome and support NACI's recommendations on vaccine dose intervals. Having as many eligible individuals as possible receive an effective first vaccine dose means that we can provide a very high level of protection to more people quickly, saving lives and reducing illness. This critical first dose will lead to reduced transmission in the community and protect those who do not develop a strong response individually. Once this is achieved, specific populations may be prioriti