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 May 14, 2021 with data up to and including MMM DD, YYYY.
On this page
- What you need to know
- Definitions
- How to report an adverse event
- Summary of adverse event following immunization reports
- Adverse event following immunization reports by vaccine name
- Adverse event following immunization reports by age and sex
- Serious and non-serious adverse events reported
- Adverse events of special interest
- Data notes
- Acknowledgements
- Suggested citation
- Related links
What you need to know up to and including MMM DD, 2021
Canada is monitoring one safety issue
{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 since last update
({New non-serious adverse events} new non-serious and {New serious adverse events} new serious)
- The benefits of vaccines authorized in Canada continue to outweigh the risks.
- 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).
- In March 2021, there were European reports of rare blood clots associated with low levels of blood platelets (thrombocytopenia). Health Canada, the Public Health Agency of Canada, provincial and territorial public health authorities have been monitoring reports in Canada and the National Advisory Committee on Immunization have been closely monitoring the emerging evidence, with all organizations taking appropriate action. Following an assessment of the evidence, Health Canada updated the product information and issued public advisories. Health Canada will continue to monitor information from the manufacturers and international regulators about this and any other potential safety issues. Provincial public health authorities will continue to update their immunization strategies as new evidence arises.
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:
- unfavourable or unintended sign (for example: skin rash)
- abnormal laboratory finding
- symptom or
- disease
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
Please note that 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:
- results in death
- is life-threatening (an event/reaction in which the patient was at real, rather than hypothetical, risk of death at the time of the event/reaction)
- requires in-patient hospitalization or prolongation of existing hospitalization
- results in persistent or significant disability/incapacity, or
- results in a congenital anomaly/birth defect
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. https://www.meddra.org/how-to-use/support-documentation
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: Investigation of safety signals.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. The data 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). While the number of doses administered have increased over time, 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
| Week report received | Weekly non-serious reports | Weekly serious reports | Cumulative non-serious reports | Cumulative serious reports | Cumulative number of doses administered | Weekly number of doses administered | Weekly non-serious report rate* | Weekly serious report rate* | Weekly report rate* |
|---|
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. COVID-19 vaccines approved for use in Canada currently include: Pfizer-BioNTech, Moderna, AstraZeneca, COVISHIELD (a version of the AstraZeneca vaccine manufactured by the Serum Institute of India and sponsored in Canada by Verity Pharmaceuticals Inc.) and Janssen (Johnson and Johnson). 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. 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 up to and including MMM DD, 2021 (n=5,015)
Figure 2: Text Description
| Vaccine name | Non-serious reports | Serious reports | Total reports | Total number of doses administered | Total non-serious report rate* | Total serious report rate* | Total report rate* |
|---|
Adverse event following immunization reports by age and sex
- Although the majority of COVID-19 vaccine doses have been administered to those over 60 years of age, the rate (number of adverse events per 100,000 doses) of reported adverse events was highest among the 30-39 year age group.
- As well, although there are similar number of doses administered to males and females, the majority of adverse event reports were among (83.1%) where sex was known (Figure 3), up to and including .
- The rate of reports for females was 44.9 per 100,000 doses administered, which was higher than the rate of reports for males at 11.5 per 100,000 doses administered.
- It is unclear if this is due in part to health care seeking behaviour (e.g. reporting adverse events) or biological differences between females and males.
- The higher proportion and rate of females and younger age groups reporting adverse events has been observed in the United States, the United Kingdom, and other countries.
- Health Canada, the Public Health Agency of Canada, 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 by up to and including MMM DD, 2021 (n=)
Figure 3: Text Description
| 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 |
|---|
1 Reports not identified as male or female were removed due to small numbers.
2 Per 100,000 doses administered.
3 Includes one report of a breastfeeding infant following maternal vaccination. Following medical review, it was determined that there is no relationship between symptoms and potential exposure to vaccine/antibodies in breast milk.
Serious and non-serious adverse events reported
- All reports of adverse events following immunization received by Health Canada and PHAC are included in this report, regardless of whether they have been linked to the vaccines. This is because we need to look at all the data available to us so we can detect any early signals of an issue.
- Health Canada, PHAC, the provinces and territories, and manufacturers continue to closely monitor the safety of COVID-19 vaccines. Serious events will be reviewed to determine if there is a new safety signal.
- If a new safety issue is found to be related to immunization, Health Canada will take appropriate action. This could include updating the product information, communicating new risks to Canadians and healthcare providers or changing the recommended use of the product.
- The individual reports represent people who reported one or more adverse events. Among the reports, the most frequently reported adverse events are presented in Figure 4.
- The majority of these adverse events are non-serious.
Figure 4. Most frequently reported adverse events (serious and non-serious combined) up to and including MMM DD, 2021 (n=)
Figure 4: Text Description
| Most frequently reported adverse events | Number of adverse events |
|---|
- 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 May 7, 2021, there were 15 reports of TTS in Canada. Of the TTS cases:
- 15 cases received COVISHEILD/AstraZeneca vaccines
- Symptom onset ranged from 6 to 24 days after vaccination
- 8 were males (age range 34 to 71 years old), 6 were females (age range 46 to 72 years old), and the sex of one was not specified
- 8 had laboratory results showing the presence of platelet factor (PF) 4 antibodies, indicating VITT (also known as VIPIT)
- Two people died
- Another TTS-related death was reported in the media but has not been yet been submitted to PHAC
- Up to and including May 7, 2021, a total of 56 deaths were reported after the administration of a vaccine. Following medical case review using the WHO-UMC causality assessment categories, it has been determined that:
- 28 are still under investigation
- 23 of these deaths are unlikely linked to a COVID-19 vaccine
- 3 deaths could not be assessed due to insufficient information.
- 2 deaths were likely linked to the vaccine
(refer to the Thrombosis with Thrombocytopenia Syndrome bullet above)
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:- Events of interest due to their association with COVID-19 infection.
- Events of interest for vaccines in general (e.g. to the specific vaccine platform 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. 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 Bell’s palsy and anaphylaxis (severe allergic reaction) (Table 1).
| AESI Category | AESI | Total |
|---|
* COVID-19 vaccines that are currently authorized 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.
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:
- 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.
- 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.
- New information contained in this report may not be comprehensive but rather represents preliminary results of data received on a weekly basis.
- Reporting jurisdictions may refer to gender as opposed to sex.
- 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.
- 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.
- The current adverse event reporting results only reflect the population that is currently prioritized for vaccination. For more information on priority vaccination for COVID-19, please see National Advisory Committee on Immunization statement.
- Adverse events of special interest are assessed according to the Brighton Collaboration criteria (if available). For example, anaphylaxis reports that meet the Brighton Collaboration criteria Level 1-3 are presented as “Anaphylaxis”. All other others reports of anaphylaxis that meet the Brighton Collaboration Level 4-5 are included in the “other allergic reactions” category.
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; April 30, 2021. 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: