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Reported side effects following COVID-19 vaccination in Canada

This page was last updated on January 19, 2024 with data up to and including MMM DD, YYYY.

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

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.

Reporting trends

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

Notes
  • Quarterly reporting rates are not provided after May 26, 2023, due to data quality issues introduced by the processing of a backlog of reports from jurisdictions.
  • As of December 3, 2023, some jurisdictions are only submitting data on doses administered for XBB.1.5 vaccines.
  • A minimum 5-week reporting lag period is used to account for time lags between someone experiencing an adverse event since vaccine administration and the event being reported to CAEFISS or Canada Vigilance. To align the numerator and denominator for rate calculations, we restrict reports to those with a date vaccine administered as of December 3, 2023. This change is due to changes in the provincial and territorial reporting frequency of data on doses administered, and ongoing data improvement initiatives.
  • Although the cumulative number of adverse event reports continues to increase over time, so does the number of doses administered. Up to and including MMM DD, 2021 all adverse event reports represented 0.056% of all doses administered.
  • 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.
  • Information on doses administered by age group was only available starting April 23, 2021 for those aged 12 and older, starting November 27, 2021 for those aged 5 to 11 years, and starting July 17, 2022 for those under the age of 5. Rates of adverse event reports and doses administered by age group are not reported before these dates.
Figure 1: Text Description

Number of COVID-19 adverse event reports received for all people up to and including (n=57,436)

Reporting period Non-serious reports-all Serious reports-all Cumulative non-serious reports-all Cumulative serious reports-all Cumulative number of doses administered-all1 Number of doses administered-all1 Non-serious reporting rate-all2 Serious reporting rate-all2 Reporting rate-all2 Cumulative serious rate-all Cumulative non-serious rate-all Cumulative total rate-all Non-serious reports-18plus Serious reports-18plus Cumulative non-serious reports-18plus Cumulative serious reports-18plus Cumulative number of doses administered-18plus1 Number of doses administered-18plus1 Non-serious reporting rate-18plus2 Serious reporting rate-18plus2 Reporting rate-18plus2 Cumulative serious rate-18plus Cumulative non-serious rate-18plus Cumulative total rate-18plus Non-serious reports-12to17 Serious reports-12to17 Cumulative non-serious reports-12to17 Cumulative serious reports-12to17 Cumulative number of doses administered-12to171 Number of doses administered-12to171 Non-serious reporting rate-12to172 Serious reporting rate-12to172 Reporting rate-12to172 Cumulative serious rate-12to17 Cumulative non-serious rate-12to17 Cumulative total rate-12to17 Non-seriousreports-5to11 Serious reports-5to11 Cumulative non-serious reports-5to11 Cumulative serious reports-5to11 Cumulative number of doses administered-5to111 Number of doses administered-5to111 Non-serious reporting rate-5to112 Serious reporting rate-5to112 Reporting rate-5to112 Cumulative serious rate-5to11 Cumulative non-serious rate-5to11 Cumulative total rate-5to11 Non-seriousreports-0to4 Serious reports-0to4 Cumulative non-serious reports-0to4 Cumulative serious reports-0to4 Cumulative number of doses administered-0to41 Number of doses administered-0to41 Non-serious reporting rate-0to42 Serious reporting rate-0to42 Reporting rate-0to42 Cumulative serious rate-0to4 Cumulative non-serious rate-0to4 Cumulative total rate-0to4

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

Notes
  • An asterisk (*) indicates a vaccine product that is no longer authorized.
  • As of December 3, 2023, some jurisdictions are only submitting data on doses administered for XBB.1.5 vaccines.
  • The "all doses" / total option includes reports that did not specify dose number.
  • A minimum 5-week reporting lag period is used to account for time lags between someone experiencing an adverse event since vaccine administration and the event being reported to CAEFISS or Canada Vigilance. To align the numerator and denominator for rate calculations, we restrict reports to those with a date vaccine administered as of June 18, 2023. This change is due to changes in the provincial and territorial reporting frequency of data on doses administered, and ongoing data improvement initiatives.
Figure 2: Text Description

Number and rate (per 100,000 doses administered) of adverse event reports received for all people by vaccine name and dose number, up to and including MMM DD, 2021 (n=54,843)

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 Non-serious reports-0to42 Serious reports-0to42 Total reports-0to42 Non-serious reporting rate-0to43 Serious reporting rate-0to43 Total reporting rate-0to43 Total number of doses administered-0to4

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

Age differences

Sex differences

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

Notes
  • As of December 3, 2023, some jurisdictions are only submitting data on doses administered for XBB.1.5 vaccines.
  • A minimum 5-week reporting lag period is used to account for time lags between someone experiencing an adverse event since vaccine administration and the event being reported to CAEFISS or Canada Vigilance. To align the numerator and denominator for rate calculations, we restrict reports to those with a date vaccine administered as of December 3, 2023. This change is due to changes in the provincial and territorial reporting frequency of data on doses administered, and ongoing data improvement initiatives.
Figure 3: Text Description

Number and rate (per 100,000 doses administered) of adverse event reports received 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.

Most common adverse events reported following immunization

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

Notes
  • An asterisk (*) indicates a vaccine product that is no longer authorized.
  • As of December 3, 2023, some jurisdictions are only submitting data on doses administered for XBB.1.5 vaccines.
  • Please note that 1 report represents 1 person and may contain information on more than 1 adverse event.
  • A minimum 5-week reporting lag period is used to account for time lags between someone experiencing an adverse event since vaccine administration and the event being reported to CAEFISS or Canada Vigilance. To align the numerator and denominator for rate calculations, we restrict reports to those with a date vaccine administered as of December 3, 2023. This change is due to changes in the provincial and territorial reporting frequency of data on doses administered, and ongoing data improvement initiatives.
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 Pfizer-BioNTech Comirnaty Bivalent (Original/Omicron BA.4/BA.5) events Number of Moderna Spikevax events Number of Moderna Spikevax (Original/OmicronBA.1) Bivalent events Number of Moderna Spikevax (Original/OmicronBA.4/5) Bivalent events Number of AstraZeneca Vaxzevria/COVISHIELD events Number of Janssen JCOVDEN events Number of Novavax Nuvaxovid events Number of Unspecified events Total number of events Rate of Pfizer-BioNTech Comirnaty events (per 100,000 doses administered) Rate of Pfizer-BioNTech Comirnaty Bivalent (Original/Omicron BA.4/BA.5) events (per 100,000 doses administered) Rate of Moderna Spikevax events (per 100,000 doses administered) Rate of Moderna Spikevax (Original/OmicronBA.1) Bivalent 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, safety signals, and deaths

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 AESI was myocarditis/pericarditis (Table 1).

To align with standard reporting practices, for AESIs with a Brighton Collaboration case definition (BCCD), only those meeting the BCCD level of certainty 1 to 3 are reported. BCCD level 4 AESIs (indicating not enough information to confirm the diagnosis) are not included in the number of reports and rate calculations for the table below.

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

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

2 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.

3 WHO guidance on pregnancy related AESIs.

  • An asterisk (*) indicates a vaccine product that is no longer authorized.
  • As of December 3, 2023, some jurisdictions are only submitting data on doses administered for XBB.1.5 vaccines.
  • Please note that 1 report represents 1 person and may contain information on more than 1 adverse event of special interest.
  • A minimum 5-week reporting lag period is used to account for time lags between someone experiencing an adverse event since vaccine administration and the event being reported to CAEFISS or Canada Vigilance. To align the numerator and denominator for rate calculations, we restrict reports to those with a date vaccine administered as of June 18, 2023. This change is due to changes in the provincial and territorial reporting frequency of data on doses administered, and ongoing data improvement initiatives.

Safety signals identified and other safety updates

To date, 2 safety signals have been confirmed: Thrombosis with thrombocytopenia syndrome (TTS) and myocarditis/pericarditis. This is based on adverse events that were reported in Canada during the COVID-19 vaccination campaign, which followed their detection internationally. These reports do not imply a causal relationship between the vaccines and the adverse event. Health Canada updated the respective product monographs to include information about these adverse events. Health Canada PHAC will continue to monitor these events.

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.
Myocarditis/pericarditis
Deaths

Acknowledgements

This quarterly 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; January 19, 2024. https://health-infobase.canada.ca/covid-19/vaccine-safety/

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