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Reported side effects following COVID-19 vaccination in Canada

We update this page every second Friday at noon Eastern Time. A summary and background information are available.

Changes to the update schedule

Please note that due to the holidays, the May 27 report will be published on May 30, 2022.

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 that 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. Report of CIOMS/WHO Working group on Vaccine Pharmacovigilance.

Adverse event report

One adverse event report, which represents 1 person, may report on more than 1 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 that may not be immediately life-threatening but requires intervention to prevent 1 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.

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 the 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, such as:

For more information, please refer to World Health Organization. COVID-19 Vaccines: Safety Surveillance Manual.
Brighton Collaboration diagnostic level of certainty

Brighton Collaboration case definitions are standardized for adverse events following immunization (AEFI). They allow AEFIs to be compared across different data sources. Clinical information on the AEFI is reviewed and categorized into 1 of 5 categories. AEFIs that meet levels 1-3 have enough information to confirm that they are a case. AEFIs that meet level 4 lack sufficient information to meet the case definition. AEFIs categorized as level 5 do not meet the case definition.

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 biweekly number of reports, as well as the biweekly reporting rate, are shown in Figure 1.

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

Data notes: 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.

Please note that as of April 29, 2022, this figure reflects biweekly counts and rates. This is due to changes in reporting schedules.

Information on doses administered by age group was only available starting April 23, 2021 for those aged 12 and older, and starting November 27, 2021 for those under the age of 12. Rates of adverse event reports and doses administered by age group are not reported before these dates.

Reports of 11-year-olds who received the Pfizer-BioNTech Comirnaty COVID-19 vaccine dose for individuals 12 years of age and older before the pediatric dose was authorized are included in the 5 to 11 age group. The 5 to 11 year age group also includes reports of individuals born in 2017 who had not yet turned 5 years old at the time of vaccination.

Figure 1: Text Description

Number of COVID-19 adverse event reports for all people up to and including (n=45,111)

Week report received Biweekly non-serious reports-all Biweekly serious reports-all Cumulative non-serious reports-all Cumulative serious reports-all Cumulative number of doses administered-all1 Biweekly number of doses administered-all1 Biweekly non-serious reporting rate-all2 Biweekly serious reporting rate-all2 Biweekly reporting rate-all2 Biweekly non-serious reports-18plus Biweekly serious reports-18plus Cumulative non-serious reports-18plus Cumulative serious reports-18plus Cumulative number of doses administered-18plus1 Biweekly number of doses administered-18plus1 Biweekly non-serious reporting rate-18plus2 Biweekly serious reporting rate-18plus2 Biweekly reporting rate-18plus2 Biweekly non-serious reports-12to17 Biweekly serious reports-12to17 Cumulative non-serious reports-12to17 Cumulative serious reports-12to17 Cumulative number of doses administered-12to171 Biweekly number of doses administered-12to171 Biweekly non-serious reporting rate-12to172 Biweekly serious reporting rate-12to172 Biweekly reporting rate-12to172 Biweekly non-serious reports-5to11 Biweekly serious reports-5to11 Cumulative non-serious reports-5to11 Cumulative serious reports-5to11 Cumulative number of doses administered-5to111 Biweekly number of doses administered-5to111 Biweekly non-serious reporting rate-5to112 Biweekly serious reporting rate-5to112 Biweekly reporting rate-5to112

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 in the muscle (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). On March 17, 2022, the authorization of the Moderna Spikevax COVID-19 vaccine was extended to children 6 to 11 years of age (50 mcg dose). Health Canada authorized the AstraZeneca Vaxzevria COVID-19 vaccine on November 19, 2021, the Janssen COVID-19 vaccine on November 23, 2021, and the Novavax Nuvaxovid COVID-19 vaccine on February 17, 2022.

While the Medicago Covifenz COVID-19 vaccine was approved for use in Canada on February 24, 2022, it was not distributed during this reporting period.

Get more information about the authorized vaccines:

For all COVID-19 vaccines being used in Canada, the rate of serious adverse event reports remains lower than that of non-serious adverse event reports. As well, rates of adverse event reports are lower after the second and third doses than after the first dose. The data for second, third, and fourth 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: 72 of the 45,111 COVID-19 adverse event reports (0.16%), involved people who received an influenza vaccine and a COVID-19 vaccine on the same day.

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

Data notes: Reports of 11-year-olds who received the Pfizer-BioNTech Comirnaty COVID-19 vaccine dose for individuals 12 years of age and older before the pediatric dose was authorized are included in the 5 to 11 age group. The 5 to 11 year age group also includes reports of individuals born in 2017 who had not yet turned 5 years old at the time of vaccination.

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 for all people by vaccine name and dose number, up to and including MMM DD, 2021 (n=45,204)

Vaccine name Non-serious reports-all2 Serious reports-all2 Total reports-all2 Non-serious reporting rate-all3 Serious reporting rate-all3 Total reporting rate-all3 Total number of doses administered-all Non-serious reports-18plus2 Serious reports-18plus2 Total reports-18plus2 Non-serious reporting rate-18plus3 Serious reporting rate-18plus3 Total reporting rate-18plus3 Total number of doses administered-18plus4 Non-serious reports-12to172 Serious reports-12to172 Total reports-12to172 Non-serious reporting rate-12to173 Serious reporting rate-12to173 Total reporting rate-12to173 Total number of doses administered-12to17 Non-serious reports-5to112 Serious reports-5to112 Total reports-5to112 Non-serious reporting rate-5to113 Serious reporting rate-5to113 Total reporting rate-5to113 Total number of doses administered-5to11

1Includes reports that did not specify dose number.

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

3Reporting 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=)

Data notes: Reports of 11-year-olds who received the Pfizer-BioNtech Comirnaty COVID-19 vaccine dose for individuals 12 years of age and older before the pediatric dose was authorized were previously included in the 12 to 17 age group. As of December 17, 2021, they are included in the 5 to 11 age group, regardless of dosage amount. The 5 to 11 year age group also includes reports of individuals born in 2017 who had not yet turned 5 years old at the time of vaccination.

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.

3The 5 to 11 year age group also includes reports of individuals born in 2017 who had not yet turned 5 years old at the time of vaccination.

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 1 report represents 1 person and may contain information on more than 1 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 Janssen 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) Rate of Janssen 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 1-3 of the Brighton Collaboration level of diagnostic certainty.

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. Although adverse events may occur after being vaccinated with a COVID-19 vaccine, they are not necessarily related to the vaccine. Health Canada and PHAC review the reports to determine whether the vaccine may have played a role.

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

To align with standard reporting practices, for AESIs with a BCD, only those meeting the BCD level of certainty 1 to 3 are reported. BCD level 4 AESIs (indicating not enough information to confirm the diagnosis) are not included in the case counts and rate calculations. BCD level 4 is presented separately in Table 1 this week to highlight the impact of this change.

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

*Brighton Collaboration Definition

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

2 Includes adverse events meeting level 4 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.

4 WHO guidance on pregnancy related AESIs.

Please note that 1 report represents 1 person and may contain information on more than 1 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 following immunization 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 biweekly. These delays may be due to jurisdictions investigating and reviewing each adverse event before 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. Every second week, we update the historical data (biweekly 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 in this report may not be comprehensive but rather represents preliminary results of data received on a biweekly 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, please consult the COVID-19 vaccination coverage webpage.
  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 2 surveillance systems are carefully merged together, the individual programs are subject to different reporting requirements and definitions. It is also possible that the biweekly report contains duplicate reports.
  8. Adverse events of special interest are assessed according to the Brighton Collaboration level of diagnostic certainty (if available).
  9. Please note, the adverse event and AESI numbers in Figure 4 and Table 1 may be adjusted following medical case review.
  10. For adverse events with low counts (less than 10) or incomplete data on doses administered, rates will not be provided.

Acknowledgements

This biweekly 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 everyone 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; May 13, 2022. https://health-infobase.canada.ca/covid-19/vaccine-safety/

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