Reported side effects following COVID-19 vaccination in Canada
This page will be updated next on September 29, 2023 at noon EST.
This page was last updated on June 9, 2023 with data up to and including MMM DD, YYYY.
On this page
- What you need to know
- How to report an adverse event
- Reporting trends
- Adverse event following immunization reports by vaccine name
- Adverse event following immunization reports by age and sex
- Most common adverse events reported following immunization
- Adverse events of special interest, safety signals and deaths
- Acknowledgements, suggested citation, and related links
What you need to know up to and including MMM DD, 2021
- No new safety signals have been identified during this reporting period.
- As of April 19, 2023, FDA’s monitoring systems and programs have not detected any safety signals for ischemic stroke following COVID-19 mRNA bivalent boosters. In Canada as well, we’ve detected no safety signal of ischemic stroke following COVID-19 mRNA bivalent boosters. Health Canada and PHAC continue to monitor this closely.
- Evidence indicates that the benefits of COVID-19 vaccines continue to outweigh the risks of the disease.
- Health Canada, the Public Health Agency of Canada (PHAC), the provinces and territories, and manufacturers continue to closely monitor the safety of COVID-19 vaccines. We’ll respond to any safety issues right away and will inform Canadians about any risks that arise in Canada.
- Of the individual reports ( of all doses administered), were considered serious ( of all doses administered).
- A total of 98,194,601 vaccine doses have been administered in Canada as of May 26, 2023, including 8,784,275 bivalent doses.
- Of the 55,145 individual reports, 793 were following a bivalent vaccine. 596 were considered non-serious (0.007% of bivalent COVID-19 doses administered) and 197 (0.002% of bivalent COVID-19 doses administered) were considered serious.
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
- 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 (56.2 reports per 100,000 doses administered) up to and including . Of the reports, were considered serious (11.0 reports per 100,000 doses administered). Overall, the rate of serious reports has remained low. Figure 1 below shows the number and rate of COVID-19 adverse event reports by reporting period, as well as the cumulative number of reports.
Figure 1. of COVID-19 vaccine adverse event reports received for and total doses administered in a 3-month reporting period, up to and including MMM DD, 2021 (n=)
The number of doses administered for this time period has decreased. This is due to historical updates and unavailable denominator data from some jurisdictions at the time of posting, as well as the vaccination campaign slowing down. As a result the reporting rates appear higher.
Notes
- On June 9, 2023, we started using a new method to provide more accurate adverse event reporting rates. A 5-week lag period between the numerator and denominator is now used to account for time lags between someone experiencing an adverse event 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 April 23, 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.
- Please note that as of June 9, 2023, this figure reflects counts and rates over a 3-month period. 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, 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=54,569)
| 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 | 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 | 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 | 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 | 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 |
|---|
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.
- Higher rates of non-serious adverse event reports are observed for each vaccine. Serious report rates remain low. Currently, rates of adverse event reports following the first dose are higher than after subsequent doses.
- The data for subsequent 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.
- A total of 98,194,601 vaccine doses have been administered in Canada as of May 26, 2023, including 8,784,275 bivalent doses.
- Of the 55,145 individual reports, 793 were following a bivalent vaccine. 596 were considered non-serious (0.007% of bivalent COVID-19 doses administered) and 197 (0.002% of bivalent COVID-19 doses administered) were considered serious.
- 218 of the 55,145 COVID-19 adverse event reports (0.40%), involved people who received an influenza vaccine and a COVID-19 vaccine on the same day. These events have been closely monitored, and no new safety concerns have been identified.
Figure 2. of adverse event reports received for by vaccine name and up to and including MMM DD, 2021 (n=)
Notes
Total includes reports that did not specify dose number.On June 9, 2023, we started using a new method to provide more accurate adverse event reporting rates. A 5-week lag period between the numerator and denominator is now used to account for time lags between someone experiencing an adverse event 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 April 23, 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
- The rate of adverse event reports was highest among the 40 to 49 year age group (82.0 reports per 100,000 doses administered), followed by those in the 30 to 39 year age group (69.6 reports per 100,000 doses administered).
- The rate of adverse event reports was lowest in the 5 to 11 year age group.
Sex differences
- Overall, most adverse event reports were from females (72.5%). The reporting rate for females was 76.5 reports per 100,000 doses administered, compared to 31.2 per 100,000 doses administered for males. However, within the youngest age groups (<18 years of age) the reporting rate is similar in males and females, or slightly higher in males.
- This may be due to differences in health care seeking behaviour (for example, reporting adverse events) as well as biological differences between females and males.
- The higher proportion and rate of adverse event reports for females has been observed in the United States, the United Kingdom, Israel, and other countries.
- Health Canada, PHAC, and provincial and territorial public health authorities will continue to monitor but have not identified this as a safety issue.
Figure 3. of adverse event reports received by up to and including MMM DD, 2021 (n=)
Notes :
On June 9, 2023, we started using a new method to provide more accurate adverse event reporting rates. A 5-week lag period between the numerator and denominator is now used to account for time lags between someone experiencing an adverse event 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 April 23, 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
- The individual reports represent people who reported 1 or more adverse events. Among the reports, the most frequently reported adverse events are presented in Figure 4. Most of these adverse events are non-serious and are captured in the product monographs.
- The most common report adverse event for all COVID-19 vaccines combined was paraesthesia with a rate of 7.91 per 100,000 doses administered.
Figure 4. of the most frequently reported adverse events by vaccine type () up to and including MMM DD, 2021 (n=)
Notes
Please note that 1 report represents 1 person and may contain information on more than 1 adverse event.On June 9, 2023, we started using a new method to provide more accurate adverse event reporting rates. A 5-week lag period between the numerator and denominator is now used to account for time lags between someone experiencing an adverse event 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 April 23, 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:
- events of interest due to their association with COVID-19 infection.
- events of interest for vaccines in general (e.g. to the specific vaccine type or adjuvants).
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.
| 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.
Please note that 1 report represents 1 person and may contain information on more than 1 adverse event of special interest.
On June 9, 2023, we started using a new method to provide more accurate adverse event reporting rates. A 5-week lag period between the numerator and denominator is now used to account for time lags between someone experiencing an adverse event 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 April 23, 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.- Numbers and rates were adjusted following receipt of additional information by the Advisory Committee on Causality Assessment (ACCA).
- Up to and including June 25, 2021, 86 reports of TTS have been reported that met level 1 to 3 of the Brighton Collaboration level of diagnostic certainty. Of the TTS reports:
- 56 reports followed vaccination with the AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine
- 22 followed vaccination with the Pfizer-BioNTech Comirnaty COVID-19 vaccine
- 8 followed vaccination with the Moderna Spikevax COVID-19 vaccine.
- For detailed information on the results of expert causality assessment for a subset of TTS reports, please visit the ACCA webpage.
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 1,167 reports of myocarditis/pericarditis that met levels 1 to 3 of the Brighton Collaboration level of diagnostic certainty. Of the myocarditis/pericarditis reports:
- 695 reports followed vaccination with the Pfizer-BioNTech Comirnaty COVID-19 vaccine
- 445 followed vaccination with the Moderna Spikevax COVID-19 vaccine
- 16 followed vaccination with the AstraZeneca Vaxzevria/COVISHIELD COVID-19 vaccine
- 4 followed vaccination with the Pfizer-BioNTech Comirnaty (Original and Omicron BA.4/BA.5) bivalent vaccine
- 3 followed vaccination with the Moderna Spikevax (Original/Omicron BA.1) bivalent vaccine
- 1 followed vaccination with the Moderna Spikevax (Original/Omicron BA.4/5) bivalent vaccine
- 1 followed vaccination with the Janssen JCOVDEN vaccine
- 1 followed vaccination with the Novavax Nuvaxovid vaccine
- the vaccine name for 1 was not specified
- The reporting rate of myocarditis/pericarditis following vaccination with Moderna Spikevax COVID-19 vaccine is higher than that of the Pfizer BioNtech Comirnaty COVID-19 vaccine, for all ages and sexes combined.
- Among the 695 reports of myocarditis/pericarditis following vaccination with the Pfizer-BioNTech Comirnaty COVID-19 vaccine (administered to those 5 years of age and older):
- symptoms started between 1 minute and 155 days after vaccination
- median age is 26 years (age range 6 to 88 years old)
- 459 were males [median age 22 years (age range 7 to 86 years old)], 228 were females [median age 39 years (age range 6 to 88 years old)], the sex of 2 were 'other', and the sex of 6 were not specified
- 268 reports followed the first vaccine dose, 381 reports followed the second vaccine dose, 40 reports followed the third vaccine dose, 4 reports followed the fourth dose, and the dose number for 2 was 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 445 reports of myocarditis following vaccination with the Moderna Spikevax COVID-19 vaccine (administered to those 6 months of age and older):
- symptoms started between 5 minutes and 113 days after vaccination
- median age is 28 years (age range 14 to 95 years old)
- 334 were males [median age 27 years (age range 14 to 95 years old)], 107 were females [median age 35 years (age range 18 to 85)], the sex of 1 was 'other', and the sex of 3 were not specified
- 83 reports followed the first vaccine dose, 321 reports followed the second vaccine dose, 34 reports followed the third dose, 5 reports followed the fourth dose, and the dose number for 2 were not specified
- 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.
Deaths
- Up to and including June 25, 2021, a total of 442 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.
- Medical case review previously used the WHO-UMC causality assessment categories to classify the status of death reports. Updated WHO guidance on causality assessment specific to vaccinations has been released. This updated user guide more accurately represents causality assessments following vaccination, so all reports with an outcome of death were updated and reclassified using the new classification system.
- Of the 442 death reports, it was not possible to assess causality for 115 reports due to missing information (not enough information to initiate causality assessment).
- Preliminary causality assessment was possible for the remaining 327 cases where there was sufficient information. Using the available information and the WHO guidance on causality assessment specific to vaccinations, we’ve determined that:
- 165 reports of death were unclassifiable due to lack of available information (not enough information to complete the preliminary assessment)
- 106 reports of death were inconsistent with causal association to the vaccine (unlikely to be linked to the vaccine)
- 52 reports of death were indeterminate (insufficient definitive evidence or conflicting evidence for causality)
- 4 deaths were consistent with causal association to immunization (see ACCA webpage)
- If additional information becomes available, cases will be re-assessed, and the causality assessment may be updated.
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; June 9, 2023. https://health-infobase.canada.ca/covid-19/vaccine-safety/
Related links
- Canadian Adverse Events Following Immunization and Surveillance System (CAEFISS)
- Immunization Monitoring Program ACTive (IMPACT)
- Canadian National Vaccine Safety Network (CANVAS)
- Canada Vigilance Program
- Drug Product Database
- Approved COVID-19 Vaccine list
- COVID-19 vaccines and treatments portal
- COVID-19 vaccination in Canada
- Date modified: