Language selection

Reported side effects following COVID-19 vaccination in Canada

We update this page every Friday at 12:00 PM Eastern Time. A summary and background information are available.

This report was last updated on MMM DD, YYYY with data up to and including MMM DD, YYYY .

On this page

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

Safety signals

Other safety updates

Definitions

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

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 AEFI).

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. 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. COVID-19 Vaccines: Safety Surveillance Manual .

How to report an adverse event

If you experience an adverse event following immunization with a COVID-19 vaccine in Canada, please contact your healthcare provider. Learn more about reporting adverse events .

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. Doses administered used for reporting rate calculations have been adjusted to account for the delay between vaccination and reporting. The data on this page 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 ). Overall, the rate of serious reports has remained low. The cumulative and weekly number of reports, as well as the weekly reporting rate, are shown in Figure 1.

Figure 1. of COVID-19 vaccine adverse event reports and total doses administered per week up to and including MMM DD, 2021 (n= )

Data note: The shaded area represents a period of time (lag time) where there may be delays in receiving and processing reporting forms. There may also be delays in receiving data on doses administered.
Figure 1: Text Description

Number of COVID-19 adverse event reports up to and including (n= )

Week report received Weekly non-serious reports Weekly serious reports Cumulative non-serious reports Cumulative serious reports Cumulative number of doses administered 1 Weekly number of doses administered 1 Weekly non-serious reporting rate 2 Weekly serious reporting rate 2 Weekly reporting rate 2

1 Doses administered used for rate calculations have been adjusted to account for the delay between vaccination and reporting.

2 Reporting rate per 100,000 doses administered.

Adverse event following immunization reports by vaccine name

Figure 2 shows the breakdown of reports by vaccine name. For doses administered by vaccine type, please visit the Vaccination Coverage report .

Health Canada authorized booster doses of Pfizer-BioNTech Comirnaty on November 9, 2021 and Moderna Spikevax on November 12, 2021 . Booster doses are administered intramuscularly to adults at least 6 months after they complete their primary series.

On November 19, 2021, the authorization of Pfizer-BioNTech Comirnaty was extended to children 5 to 11 years of age (10 mcg dose). Health Canada authorized the AstraZeneca Vaxzevria COVID-19 vaccine on November 19, 2021 and the Janssen COVID-19 vaccine on November 23, 2021 under the Food and Drug Regulations . Get more information about the authorized vaccines:

Higher rates of non-serious adverse event reports are observed for each vaccine, with serious report rates continuing to remain low. Currently, rates of adverse event reports following the second dose are lower than after the first dose. The data for second and third doses do not take into account which vaccine an individual received for previous doses. Generally, non-serious adverse event reports are consistent with information provided in the vaccine product pages.

Note: 28 of the 28,825 COVID-19 adverse event reports (0.10%), involved people who received an influenza vaccine and a COVID-19 vaccine on the same day.

Figure 2. of adverse event reports by vaccine name and dose number up to and including MMM DD, 2021 (n=28,875)

Total includes reports that did not specify dose number.
Figure 2: Text Description

Number and rate (per 100,000 doses administered) of adverse event reports by vaccine name and dose number up to and including MMM DD, 2021 (n=28,875)

Vaccine name Non-serious reports 2 Serious reports 2 Total reports 2 Total number of doses administered Non-serious reporting rate 3, 4 Serious reporting rate 3, 4 Total reporting rate 3, 4

1 Includes reports that did not specify dose number.

2 Includes reports that contain information on more than one vaccine name.

3 Reporting rates for dose 3 have been omitted this week due to delays in receiving data on the number of 3rd doses administered, which are required for rate calculations.

4 Reporting rate per 100,000 doses administered.

* Dose 1 rate calculations for Moderna last week were underestimated due to an update in the doses administered data. The data has since been updated.

Adverse event following immunization reports by age and sex

Figure 3. of adverse event reports by up to and including MMM DD, 2021 (n= )

Figure 3: Text Description

Number and rate (per 100,000 doses administered) of adverse event reports by age group and sex up to and including (n= )

Age group Total Male Female Other Unknown Number of doses administered by age group Number of doses administered to males Number of doses administered to females Total number of doses administered 1 Reporting rate by age group Male reporting rate 2 Female reporting rate 2 Total reporting rate (males and females) 1,2

1 Reports not identified as male or female were removed due to small numbers.

2 Reporting rate per 100,000 doses administered.

3 Also includes reports of individuals turning 12 years of age the year they are vaccinated.

Serious and non-serious adverse events reported

Figure 4. of the most frequently reported adverse events by vaccine type ( ) up to and including MMM DD, 2021 (n= )

Please note that one report represents one person and may contain information on more than one adverse event.
Figure 4: Text Description

Number and rate (per 100,000 doses administered) of the most frequently reported adverse events by vaccine type up to and including MMM DD, 2021 (n= )

Most frequently reported events 1 Number of Pfizer-BioNTech Comirnaty events Number of Moderna Spikevax events Number of AstraZeneca Vaxzevria/COVISHIELD events Number of Unspecified events Total number of events Rate of Pfizer-BioNTech Comirnaty events (per 100,000 doses administered) Rate of Moderna Spikevax events (per 100,000 doses administered) Rate of AstraZeneca Vaxzevria/COVISHIELD events (per 100,000 doses administered) Total rate of events (per 100,000 doses administered)

1 Includes both serious and non-serious adverse events.

2 Includes adverse events meeting levels 1-4 of the Brighton Collaboration level of diagnostic certainty.

3 Includes adverse events meeting levels 1-3 of the Brighton Collaboration level of diagnostic certainty.

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

Adverse events of special interest

Adverse events of special interest (AESI) are pre-specified medically significant events that have the potential to be causally associated with a vaccine product. They must be carefully monitored and confirmed by further special studies. AESI can be serious or non-serious and can include:

The list of AESI s below takes into consideration the lists of AESI s from these expert groups, manufacturers and regulatory authorities:

The AESI list changes based on the evolving safety profile of vaccines. It is important to recall that although these adverse events may occur after being immunized with a COVID-19 vaccine in Canada, they are rare and may not necessarily be related to the vaccine. Health Canada and PHAC review the reports to determine whether the vaccine may have played a role in the occurrence of these events.

Up to and including , the most commonly reported AESI s were myocarditis/pericarditis and anaphylaxis (Table 1).

Table 1. of reported adverse events of special interest by vaccine type ( ) up to and including April 30, 2021 (n= ).
AESI Category AESI Total

1 Includes adverse events meeting levels 1-4 of the Brighton Collaboration level of diagnostic certainty.

2 Includes adverse events meeting levels 1-3 of the Brighton Collaboration level of diagnostic certainty.

3 COVID-19 vaccines that are currently authorized in Canada cannot cause an infection because they do not contain the live virus. While they are all highly effective at preventing severe COVID-19 illness and death, no vaccine is 100% effective, and some COVID-19 cases will still occur. For vaccines that have a two-dose regimen, protection begins 14 days after the first dose, and 7 to 14 days after the second dose.

* Please note, numbers may be adjusted following medical case review.

Please note that one report represents one person and may contain information on more than one adverse event of special interest.

Detailed information on safety signals, other safety updates and deaths

These reports do not imply a causal relationship between the vaccine and the adverse event. Some unrelated medical events do occur by chance after immunization, especially when millions of people are being vaccinated.

Thrombosis with thrombocytopenia syndrome
Guillain-Barré Syndrome
Myocarditis/pericarditis
Capillary leak syndrome
Deaths

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 and processing reporting forms which may contribute to variations in the amount of reports presented weekly. 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. Each week, we update the historical data (weekly and cumulative number of reports) to include any delayed reporting forms from earlier weeks.
  3. 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.
  4. New information contained in this report may not be comprehensive but rather represents preliminary results of data received on a weekly basis.
  5. Reporting jurisdictions may refer to gender as opposed to sex.
  6. 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 .
  7. 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.
  8. Currently, only COVID-19 mRNA vaccines are approved for Canadians 12 years of age and older. Only Pfizer-BioNTech Comirnaty is approved for Canadians 5 to 11 years of age.
  9. Adverse events of special interest are assessed according to the Brighton Collaboration level of diagnostic certainty (if available).

Acknowledgements

This weekly report would not be possible without the collaboration of federal, provincial and territorial public health partners as well as everyone taking part in the COVID-19 vaccination rollout in Canada.

We would also like to thank each individual who took the time to submit an adverse event report for their contribution to vaccine safety in Canada.

Suggested citation

Public Health Agency of Canada. Canadian COVID-19 vaccination safety report. Ottawa: Public Health Agency of Canada; December 10, 2021. https://health-infobase.canada.ca/covid-19/vaccine-safety/

Related links

Date modified: