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COVID-19 vaccine safety in Canada

This page provides information about any adverse events following immunization that individuals have reported after receiving a COVID-19 vaccine in Canada. Even though an adverse event is reported, it is not necessarily related to the vaccine. We update this page every Friday at 12:00 PM Eastern Time.

On this page

What you need to know up to and including MMM DD, 2021

No safety signals

(potential safety issues) have been identified

{New adverse events reported since last report}

New adverse event following immunization reports since last update

({New non-serious adverse events} new non-serious and {New serious adverse events} new serious)

{Total adverse events}

Total adverse event following immunization reports

({Percent non-serious (total)} of all doses administered)

{Total non-serious adverse events}

Total adverse event following immunization reports were non-serious

({Percent non-serious (total)} of all doses administered)

{Total serious adverse events}

Total adverse event following immunization reports were serious

({Percent serious (total)} of all doses administered)

{Total doses administered}

Total doses administered


Adverse Event Following Immunization (adverse event)

An adverse event is any untoward medical occurrence which follows immunization. It isn’t necessarily causally related to the usage of the vaccine. The adverse event may be any:

For more information, please refer to the Council for International Organizations of Medical Sciences (CIOMS) and World Health Organization (WHO). Definition and Application of Terms for Vaccine Pharmacovigilance. Report of CIOMS/WHO Working group on Vaccine Pharmacovigilance. Geneva: CIOMS and WHO; 2012

Adverse event report

Please note that one adverse event report, which represents one person, may report on more than one symptom (i.e a serious or non serious adverse event following immunization, or adverse event).

Serious adverse event

An event is considered serious if it:

Medically important event

An event which may not be immediately life-threatening but requires intervention to prevent one of the outcomes listed above and may also be considered as serious. This is based on the International Council on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use. See:

International Council on Harmonisation (ICH). Support Documentation. Medical Dictionary for Regulatory Activities.

Adverse Events of Special Interest (AESI)

This is a pre-specified medically significant event that has the potential to be causally associated with a vaccine product. It must be carefully monitored and confirmed by further special studies.

For more information, please refer to World Health Organization. COVID-19 Vaccines: Safety Surveillance Manual.
Safety signal

Information indicating a new and potentially causal association between a vaccine and an event that could affect health. The event is either unknown or incompletely documented. It could also indicate a new aspect of a known association. The primary purpose of vaccine post-market surveillance is to detect safety concerns. These concerns include a possible increase in the severity or frequency of expected adverse events, or one or more unexpected events (i.e., an event that is not consistent with Canadian product information or labelling).

For more information, please refer to World Health Organization: Investigation of safety signals.

Summary of adverse event following immunization reports

The information on this page reflects detailed case information data from the Public Health Agency of Canada’s Canadian Adverse Events Following Immunization Surveillance System (CAEFISS) and Health Canada’s Canada Vigilance program. The data may undergo changes as more information about cases becomes available.

There have been a total of reports ( reports per 100,000 doses administered) up to and including . Of the reports, were considered serious ( reports per 100,000 doses administered). The total and weekly number of reports are shown in Figure 1.

Figure 1. number of COVID-19 vaccine reports up to and including MMM DD, 2021 (n=)

Figure 1: Text Description
Number of COVID-19 vaccine reports up to and including (n=)
Week report received Weekly non-serious reports Weekly serious reports Total non-serious reports Total serious reports

Adverse event following immunization reports by vaccine name

Figure 2 shows the breakdown of reports by vaccine name. Although the number of doses administered is not available by vaccine name, doses of Pfizer-BioNTech and doses of Moderna have been distributed within Canada.

Figure 2. Number of reports by vaccine name up to and including MMM DD, 2021 (n=)

Figure 2: Text Description
Number of reports by vaccine name up to and including MMM DD, 2021
Vaccine name Non-serious reports Serious reports Total reports

Adverse event following immunization reports by age and sex

Among the population prioritized for vaccination, the number of reported adverse events was highest among those aged , where age was known. Most of the reports involved where sex was known (Figure 3), up to and including . This reflects the groups that have been vaccinated to date in Canada.

Figure 3. Reports by up to and including MMM DD, 2021 (n=)

Figure 3: Text Description
Reports by age group and sex up to and including (n=)
Age group Total Male Female Other Unknown

Serious and non-serious adverse events reported

Figure 4. Classification of serious adverse events as of MMM DD, 2021

Data notes

The data presented in this report are estimates and may not accurately represent national COVID-19 vaccine adverse events for the following reasons:

  1. There may be delays in receiving reporting forms. These delays may be due to jurisdictions investigating and reviewing each adverse event prior to submitting the information to PHAC. There are also limitations to reporting practices such as underreporting, missing information, and differing adverse event reporting practices across jurisdictions in Canada.
  2. Information is collected on individuals for whom an report was submitted, not on the total number of individuals who experience an adverse event as not every adverse event is reported.
  3. New information contained in this report may not be comprehensive but rather represents preliminary results of data received on a weekly basis.
  4. Reporting jurisdictions may refer to gender as opposed to sex.
  5. Information on COVID-19 vaccine doses administered are obtained from provincial and territorial partners or their websites. More details on the number of COVID-19 vaccine doses administered are available.
  6. The data presented in this report represent combined numbers from both CAEFISS and the Canada Vigilance program. Canada Vigilance receives reports directly from vaccine manufacturers, healthcare professionals and consumers. CAEFISS receives reports from regional public health authorities. Although data from these two surveillance systems are carefully merged together, the individual programs are subject to different reporting requirements and definitions. It is also possible that the weekly report contains duplicate reports.
  7. The current adverse event reporting results only reflect the population that is currently prioritized for vaccination. For more information on priority vaccination for COVID-19, please see National Advisory Committee on Immunization statement.

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