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Reported side effects following COVID-19 vaccination in Canada

Summary Weekly report Archived reports

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

No new safety signals have been identified in Canada

(three continue to be monitored)

{Total doses administered}

Total doses administered

{Total adverse events}

Total adverse event following immunization reports

({Percent non-serious (total)} of all doses administered)

{Total non-serious adverse events}

Total adverse event following immunization reports that were non-serious

({Percent non-serious (total)} of all doses administered)

{Total serious adverse events}

Total adverse event following immunization reports that were serious

({Percent serious (total)} of all doses administered)

{New adverse events reported since last report}

New adverse event following immunization reports received between September 11 to 17, 2021.

({New non-serious adverse events} new non-serious and {New serious adverse events} new serious)

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 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 report 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.
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 report rate2 Weekly serious report rate2 Weekly report rate2

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

2 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. On September 16, 2021, Health Canada authorized requests by vaccine manufacturers Pfizer-BioNTech and Moderna to change the brand names of their COVID-19 vaccines. These requests were made under the amended Food and Drug Regulations. Both vaccines have brand name changes; the Pfizer-BioNTech vaccine became Comirnaty and the Moderna vaccine became Spikevax. The AstraZeneca’s brand name change to Vaxzevria was authorized under the Interim Order. These new names are the same ones the manufacturers have given them internationally. Get more information about the authorized vaccines:

The COVISHIELD version of the AstraZeneca vaccine which provided a temporary supply to Canadians through the Interim Order respecting the importation, sale and advertising of drugs for use in relation to COVID-19 expired with the Interim Order on September 16, 2021. However, we will continue to monitor for safety.

While the Janssen vaccine has been approved for use in Canada, it has not yet been distributed during this reporting period.

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 events following the second dose are lower than after the first dose. The data for second doses do not take into account which vaccine an individual received for their first dose. Generally, reported non-serious adverse events are consistent with information provided in the vaccine product pages.

Figure 2. of adverse event reports by vaccine name and dose number up to and including MMM DD, 2021 (n=16,134)

Total includes reports that did not specify first or second dose.
Figure 2: Text Description
Number and report rate (per 100,000 doses administered) of adverse event reports by vaccine name and dose number up to and including MMM DD, 2021 (n=16,134)
Vaccine name Non-serious reports2 Serious reports2 Total reports2 Total number of doses administered Non-serious report rate3 Serious report rate3 Total report rate3

1Includes reports that did not specify first or second dose.

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

3Per 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 Rate by age group Male rate2 Female rate2 Total rate (males and females)1,2

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

2Per 100,000 doses administered.

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 reports meeting levels 1-4 of the Brighton Collaboration case definition.

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 reports meeting levels 1-4 of the Brighton Collaboration case definition.

2 Includes reports meeting levels 1-3 of the Brighton Collaboration case definition.

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
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 accross jurisdictions in Canada.
  2. 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.
  3. New information contained in this report may not be comprehensive but rather represents preliminary results of data received on a weekly basis.
  4. Reporting jurisdictions may refer to gender as opposed to sex.
  5. 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.
  6. 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.
  7. Currently, only COVID-19 mRNA vaccines are approved for Canadians 12 years of age and older.
  8. 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; September 24, 2021. https://health-infobase.canada.ca/covid-19/vaccine-safety/

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