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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 administered1 Weekly number of doses administered1 Weekly non-serious reporting rate2 Weekly serious reporting rate2 Weekly reporting rate2

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 the 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: 22 of the 26,734 COVID-19 adverse event reports (0.08%), 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=26,784)

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=26,784)
Vaccine name Non-serious reports2 Serious reports2 Total reports2 Total number of doses administered Non-serious reporting rate3, 4 Serious reporting rate3, 4 Total reporting rate3, 4

1Includes reports that did not specify dose number.

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

3Reporting 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.

4Reporting rate per 100,000 doses administered.

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 administered1 Reporting rate by age group Male reporting rate2 Female reporting rate2 Total reporting rate (males and females)1,2

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

2Reporting rate per 100,000 doses administered.

3Also 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 events1 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)

1Includes both serious and non-serious adverse events.

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

3Includes 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 AESIs below takes into consideration the lists of AESIs 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 AESIs were myocarditis/pericarditis and Bell’s Palsy (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 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
  • Thrombosis with thrombocytopenia syndrome (TTS) is characterized as blood clotting with low platelet levels. Vaccine-Induced Immune Thrombotic Thrombocytopenia (VITT), also known as Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT), is characterized as TTS that seems to be vaccine-induced due to the laboratory-confirmed presence of platelet factor (PF) 4 antibodies.
  • Up to and including June 25, 2021, there were 89 reports of TTS that met Level 1 to 4 of Brighton Collaboration level of diagnostic certainty. Of the TTS reports:
    • 64 reports followed vaccination with an AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine, 19 followed vaccination with a Pfizer-BioNTech Comirnaty COVID-19 vaccine, and six followed vaccination with a Moderna Spikevax COVID-19 vaccine.
  • Of the 64 TTS reports following a AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine:
    • Symptoms started between 1 and 37 days after vaccination.
    • Median age is 56 years (age range 19 to 88 years old)
    • 34 were males [median age 57 years (age range 34 to 73 years old)], 29 were females [median age 55 years (age range 19 to 88 years old)], and the age and sex of one was not specified.
    • 58 reports following the first vaccine dose, and the dose number for six were not specified
    • 38 had laboratory results showing the presence of platelet factor (PF) 4 antibodies, indicating VITT (also known as VIPIT).
    • Six people died.
Guillain-Barré Syndrome
  • Up to and including July 9, 2021, there are a total of 103 reports of GBS that met Level 1 to 4 of Brighton Collaboration level of diagnostic certainty. Of the GBS reports:
    • 37 reports followed vaccination with an AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine, 44 followed vaccination with a Pfizer-BioNTech Comirnaty COVID-19 vaccine, and 22 followed vaccination with a Moderna Spikevax COVID-19 vaccine.
    • Current results show the reporting rate of GBS following AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccination is higher than the reporting rate of GBS following Pfizer-BioNTech Comirnaty COVID-19 vaccine or Moderna Spikevax COVID-19 vaccine. As well, the number of reports of GBS following AstraZeneca Vaxzevria/COVISHIELD vaccination are higher than would normally be expected in the general population.
  • Among the 37 reports of GBS following an AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine:
    • Symptoms started between 6 hours and 25 days after vaccination
    • Median age is 56 years (age range 40 to 77 years old)
    • 26 were males [median age 56 years (age range 40 to 66 years old)], 9 were females [median age 53 years (age range 40 to 77 years old)], and the age and sex of two were unspecified
    • 27 reports following the first vaccine dose, and the dose number for 10 were unspecified
Myocarditis/pericarditis
  • Myocarditis is inflammation of the heart muscle and pericarditis is inflammation of the lining around the heart.
  • Up to and including June 25, 2021, there were 1,329 reports of myocarditis/pericarditis that met Level 1 to 4 of Brighton Collaboration level of diagnostic certainty. Of the myocarditis/pericarditis reports:
    • 823 reports followed vaccination with a Pfizer-BioNTech Comirnaty COVID-19 vaccine, 479 followed vaccination with a Moderna Spikevax COVID-19 vaccine, 24 followed vaccination with an AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine, and the vaccine name of three were unspecified.
  • The reporting rate of myocarditis/pericarditis following vaccination with Moderna Spikevax is approximately double that of Pfizer BioNtech Comirnaty, for all ages and sexes combined.
  • Among the 823 reports of myocarditis/pericarditis following Pfizer-BioNTech Comirnaty COVID-19 vaccine (administered to those 12 years of age and older):
    • Symptoms started between 5 minutes and 101 days after vaccination
    • Median age is 27 years (age range 11 to 93 years old)
    • 503 were males [median age 22 years (age range 12 to 84 years old)], 292 were females [median age 39 years (age range 12 to 93 years old)], the sex of two was 'other', and the sex of 26 were unspecified
    • 345 reports following the first vaccine dose, 362 reports following the second vaccine dose, two reports following the third vaccine dose, and the dose number for 114 were not specified
    • Current analyses show the number of reports of myocarditis/pericarditis following the Pfizer-BioNTech Comirnaty COVID-19 vaccine is higher than what would be expected in the general population of males and females less than 30 years old and primarily following the second dose.
  • Among the 479 reports of myocarditis following vaccination with a Moderna Spikevax COVID-19 vaccine (administered to those 12 years of age and older):
    • Symptoms started between 5 minutes and 74 days after vaccination
    • Median age is 28 years (age range 17 to 95 years old)
    • 340 were males [median age 27 years (age range 17 to 95 years old)], 129 were females [median age 35 years (age range 18 to 88)], the sex of two were 'other', and the sex of eight were unspecified
    • 125 reports following the first vaccine dose, 308 reports following the second vaccine dose, one report following the third dose, and the dose number for 45 were unspecified
    • Current analyses show the number of reports of myocarditis/pericarditis following the Moderna Spikevax COVID-19 vaccine is higher than what would be expected in the general population, particularly among males and females less than 40 years old and following the second dose.
  • Evidence is evolving and investigations into the association between myocarditis/pericarditis and mRNA vaccines continue.
Capillary leak syndrome
  • Up to and including July 9, 2021, there have been two reports of capillary leak syndrome that have been medically reviewed to verify the diagnosis. The events occurred following a first dose of AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine.
Deaths
  • Up to and including June 25, 2021, a total of 227 reports with an outcome of death were reported following vaccination. Although these deaths occurred after being vaccinated with a COVID-19 vaccine, they are not necessarily related to the vaccine. Based on the medical case review using the WHO-UMC causality assessment categories, it has been determined that:
    • 83 reports of death are unlikely linked to a COVID-19 vaccine
    • 98 reports of death could not be assessed due to insufficient information
      • Among the 98 that could not be assessed, 1 reported death followed a report of TTS (Pfizer BioNTech Comirnaty)
    • 46 reports of death are still under investigation
      • Among the 46 still under investigation, 6 of the reported deaths followed a diagnosis of TTS (AstraZeneca Vaxzevria/COVISHIELD)

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.
  9. Adverse events of special interest are assessed according to the Brighton Collaboration criteria (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; November 26, 2021. https://health-infobase.canada.ca/covid-19/vaccine-safety/

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