Statement from the Chief Public Health Officer of Canada on December 3, 2021


December 3, 2021 | Ottawa, ON | Public Health Agency of Canada

The COVID-19 pandemic continues to create stress and anxiety for many Canadians, particularly those who do not have ready access to their regular support networks. Through the Wellness Together Canada online portal, people of all ages across the country can access immediate, free and confidential mental health and substance use supports, 24 hours a day, seven days a week.

Today, Canada's National Advisory Committee on Immunization (NACI) provided updated advice on COVID-19 mRNA vaccine booster doses as well as recommendations on the use of mRNA COVID-19 vaccines in adolescents and young adults, specifically.

NACI has reaffirmed that the benefits of receiving an mRNA COVID-19 vaccine continue to outweigh any potential risks of experiencing rare side effects following vaccination with an mRNA vaccine, including the rare risk of vaccine-associated myocarditis and/or pericarditis most often seen in males aged 12 to 29 years. NACI also recommends, and health authorities in Canada agree, that immunization in those who are eligible - but have yet to receive their primary series - should continue to remain the top priority, in Canada and around the world.

Regarding boosters, NACI considered emerging evidence on waning protection of vaccines over time and the safety and potential benefits of mRNA vaccine booster doses. In the context of the Delta variant, evidence suggests that vaccine effectiveness against infection and symptomatic disease decreases with time, and possibly against severe illness as well, especially in older individuals. No additional safety concerns were noted following mRNA vaccine booster doses. The rare risk of myocarditis and/or pericarditis appears to be lower after the booster dose than after the second dose of the primary series --though higher than after the first dose. Based on this, NACI has increased the strength of their recommendations to now say --a booster dose of an authorized mRNA COVID-19 vaccine should be offered 6 months or more after completion of a primary COVID-19 vaccine series. This strong recommendation has also been expanded to include adults in the following populations:

  • People aged 50 years or older
  • Adults living in seniors' long-term care or other congregate living settings that provide care for seniors
  • People who received an exclusively viral vector COVID-19 vaccine series, consisting of only AstraZeneca/COVISHIELD and/or the Janssen COVID-19 vaccine
  • Adults in or from First Nations, Inuit and Métis communities
  • Frontline healthcare workers having direct close physical contact with patients

NACI further recommends that a booster dose of an authorized mRNA COVID-19 vaccine may be offered 6 months or more after completion of a primary COVID-19 vaccine series to adults aged 18-49 years, with consideration of jurisdictional and individual risks.

Finally, with respect to vaccination of adolescents and young adults, NACI considered new Canadian and international data that suggests the rare risk of myocarditis after receiving an mRNA COVID-19 vaccine may be lower with the Pfizer-BioNTech Comirnaty 30 microgram vaccine as compared to the Moderna Spikevax 100 microgram vaccine. These data also show that a longer interval between the first and second dose in the primary vaccination series results in stronger immune response and higher vaccine effectiveness and that longer intervals may also be associated with a lower risk of myocarditis and/or pericarditis.

Accordingly, for adolescents and young adults aged 12 to 29 years, NACI now recommends the use of Pfizer-BioNTech Comirnaty vaccine is preferred over the use of the Moderna Spikevax vaccine to start or complete a primary vaccine series. NACI further recommends that the second dose of a primary mRNA COVID-19 vaccine series should be provided 8 weeks after the first dose.

The Public Health Agency of Canada (PHAC) continues to monitor COVID-19 epidemiological indicators to quickly detect, understand and communicate emerging issues of concern. The following is a brief summary of the latest national numbers and trends.

Since the start of the pandemic, there have been 1,798,872 cases of COVID-19 and 29,737 deaths reported in Canada. These cumulative numbers tell us about the overall burden of COVID-19 illness to date, while the number of active cases, now at 26,611, and 7-day moving averages indicate current disease activity and severity trends.

Surveillance data continue to show significant regional variation in COVID-19 disease activity across the country. Nationally, daily case counts have been gradually rising, with high infection rates persisting in many areas. During the latest 7 day period (Nov 26-Dec 2), an average of 2,821 new cases were reported, which is an increase of 8% compared to the previous week. Currently, hospitalisation and critical care admission trends are still declining slowly, but if infection rates accelerate, trends could begin to rise again. The latest provincial and territorial data show that an average of 1,540 people with COVID-19 were being treated in Canadian hospitals each day during the most recent 7-day period (Nov 26-Dec 2), which is 4% lower than last week. This includes, on average, 465 people who were being treated in intensive care units (ICU), 1% less than last week and an average of 19 deaths were reported daily (Nov 26-Dec 2). Keeping infection rates down remains key to avoiding renewed increases in severe illness trends over the coming weeks and months as well as to ease longer term strain on the health system, particularly in heavily impacted areas.

While Delta continues to represent the vast majority of recent COVID-19 cases in Canada, as of December 2, 2021, there have been 11 cases with the newly designated variant of concern (VOC), Omicron, reported in Ontario, Quebec, Alberta and British Columbia. As we continue to assess the significance and impact of this new VOC, Canadians are urged to remain vigilant and continue maintaining layers of protection.

Regardless of which SARS-CoV-2 variant is predominating, we know that vaccination, in combination with public health measures and individual practices, work to reduce disease spread and severe outcomes. In particular, evidence continues to demonstrate that a complete two-dose series of Health-Canada approved COVID-19 vaccines provides substantial protection against severe illness, particularly among younger age groups. Based on the latest data from 9 provinces and territories for the population aged 12 years or older, in recent weeks (October 17 - November 13, 2021) and adjusting for age, average weekly rates indicate that unvaccinated people were significantly more likely to be hospitalized with COVID-19 compared to fully vaccinated people.

  • Among youth and adults aged 12 to 59 years, unvaccinated people were 37 times more likely to be hospitalized with COVID-19 than fully vaccinated people.
  • Among older adults aged 60 years or older, unvaccinated people were 18 times more likely to be hospitalized with COVID-19 than fully vaccinated people.

As of December 2, 2021, provinces and territories have administered over 60.8 million doses of COVID-19 vaccines. With the recent approval of the pediatric formulation of Pfizer-BioNTech Comirnaty COVID-19 vaccine for use in children aged 5 to 11 years, the population eligible for vaccination in Canada has expanded and now represents an estimated 95% of the total population. The latest provincial and territorial data indicate that close to 80% of the total population has received at least one dose of COVID-19 vaccine and close to 76% are now fully vaccinated. Age-specific vaccine coverage data, as of November 27, 2021, show that over 89% of people 40 years or older have at least one dose and over 86% are fully vaccinated, while 86% of younger adults aged 18-39 years have at least one dose and over 81% are fully vaccinated. As the pediatric vaccination program rolls out across Canada, I encourage parents and guardians to seek credible information from trusted sources, such as to make informed decisions about COVID-19 vaccination. I also urge healthcare providers and others to support children and their caregivers by listening, sharing credible information, and engaging in respectful dialogue.

While COVID-19 is still circulating in Canada and internationally, vaccination in combination with timed and targeted public health measures and individual protective practices continue to be important for slowing COVID-19 infection rates and reducing the impact on healthcare capacity. This includes staying home/self-isolating if you have symptoms; being aware of risks associated with different settings; following local public health advice and consistently maintaining individual precautions. In particular, properly wearing a well-fitted and well-constructed face mask when in public or private spaces with others outside of your immediate household, avoiding crowding, and getting the best ventilation possible in indoor spaces, are layers of protection that can reduce your risk in all settings. We can also stay healthier by getting up-to-date with recommended vaccines, such as influenza and other routine vaccines for children and adults.

For additional information regarding vaccination in your area, reach out to your local public health authorities, healthcare provider, or other trusted and credible sources, such as and provides a broad range of COVID-19 information and resources to help Canadians understand the benefits of being vaccinated against COVID-19.

Canadians can also go the extra mile by sharing credible information on COVID-19 risks and prevention practices and measures to reduce COVID-19 in communities. Read my backgrounder to access more COVID-19 Information and Resources on ways to reduce the risks and protect yourself and others, including information on COVID-19 vaccination.


Media Relations
Public Health Agency of Canada

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