Adverse events following immunization in Canada: Dashboard

It includes reports from those vaccinated in Canada between January 1, 2015, and December 31, 2024. The dashboard will be updated regularly.

On this page

• Spotlight on 2024
• Reports over time
• Reports by age and sex
• Reports by vaccine
• Reports by adverse event

Medical events sometimes occur after someone is vaccinated and are called AEFIs. Information about AEFIs is collected by healthcare providers and sent to public health authorities. Most AEFIs are common and mild, such as fever, a sore arm, or muscle aches. Some medical events happen by chance after, but not necessarily because of, vaccination. These events may be unrelated but took place around the same time as the vaccination.

Spotlight on 2024

In 2024, there were:

In 2024, no vaccine safety signals of concern were identified. A safety signal is information from the data that something unusual may be happening after vaccination that needs to be investigated further. Vaccine safety signals are continuously monitored by:

• the Public Health Agency of Canada (PHAC)
• Health Canada (HC)
• public health authorities in the provinces and territories, who are responsible for immunization programs
• manufacturers

Reports over time

Figure 1 shows the number of AEFI reports submitted to CAEFISS over a 10 year period. The percentage reported as serious is low, at about 10% year over year. Users can filter the data to display either COVID-19 or non-COVID-19 vaccines.

Definition of a serious adverse event report

The largest vaccination campaign in Canada’s history, starting in 2021, took place during the COVID-19 pandemic. Over 100 million vaccine doses were administered during the vaccination campaign in a short period of time, and there was increased attention and awareness around the COVID-19 vaccines. The large number of vaccinations and attention led to more adverse events being reported. Despite this, the percentage of serious reports remained low and comparable to previous years. Safety was closely monitored, and, when identified, safety signals were investigated and addressed.

Figure 1: Notes

• Visit Understanding the data for additional information, definitions and limitations.
• Reporting may vary somewhat from year to year if there are significant program changes, such as large-scale vaccination campaigns.

Reports by age and sex

Figure 2 shows the number of AEFI reports by age group, sex, seriousness and year. Users can filter the data to display either COVID-19 or non-COVID-19 vaccines. Overall, the highest number of reported AEFIs was among infants and young children. There was an exception in 2021 and 2022 where the highest number of reports was among adults (aged 25-49 years), likely due to increased vaccination in this age group from the mass COVID-19 vaccination campaign.

In Canada, many different types of vaccines are given every year. Differences in the number of AEFI reports across age groups are influenced by how vaccines are recommended across the lifespan. For example, infants and young children may receive several vaccines as part of the routine immunization schedule to protect against many diseases. Meanwhile, adolescents and adults who have completed the series recommended in childhood receive fewer. The exception was during the COVID-19 vaccination program, where vaccines were recommended for all age groups but the coverage in children was low.

Figure 2: Notes

• Visit Understanding the data for additional information, definitions and limitations.
• Reports with undisclosed age and/or sex include individuals who chose not to give this information or it was not known at the time of reporting. Reports with undisclosed age or sex are excluded from this figure.
• To protect privacy, data are not shown for groups with less than five reports. To prevent the calculation of these numbers, other data are suppressed.

Reports by vaccine

Figure 3 shows the number of AEFI reports by vaccine, vaccine group, seriousness and year. The higher number of AEFI reports following some vaccines can reflect the number of doses of these vaccines administered each year. This is most evident by the reports following COVID-19 vaccines for the years 2021 and 2022 especially.

Vaccines in this figure have been grouped into categories that are based on recommendations for vaccine use in Canada and reflect the typical age groups or situations when they are administered. Also of note, if multiple vaccines are given at the same visit, the same AEFI report is counted for each vaccine.

A list of vaccines in this dashboard and their abbreviations can be downloaded: Vaccine list and abbreviations (CSV, 12 KB).

Figure 3: Notes

• Visit Understanding the data for additional information, definitions and limitations.
• Each AEFI report represents one person who experienced one or more adverse events after receiving one or more vaccines (co-administration). One report can include several vaccines. Therefore, the number of reports by vaccine in a given year may be higher than the number of individual AEFI reports in that year.
• To protect privacy, data are not shown for groups with less than five reports. To prevent the calculation of these numbers, other data are suppressed.

Reports by adverse event

Figure 4 shows the most frequently reported adverse events by year and by vaccine. Most of these adverse events are mild and some of them are expected immune responses to immunization. For this figure, if a report had multiple adverse events, such as both a fever and a rash, each event is counted separately. Therefore, the total number of events is greater than the number of reports received.

AEFIs are grouped in CAEFISS using a standardized list of terms from the Medical Dictionary for Regulatory Activities (MedDRA), known as Preferred Terms. For this figure, similar Preferred Terms were combined, for example, “Injection site pain” and “Vaccination site pain”, to avoid repetition.

Learn more about MedDRA coding

Figure 4: Notes

• Visit Understanding the data for more information, definitions and limitations.
• Each AEFI report can include one or more MedDRA terms to represent the event being reported. Therefore, the number of reports by adverse event in a given year may be higher than the number of individual AEFI reports in that year.
• To protect privacy, only terms that appear in at least five reports for the same vaccine in one year are included. This is so individuals in very small groups cannot be identified. To avoid repetition and improve clarity, we combined similar terms, such as “Injection site pain” and “Vaccination site pain”.

Acknowledgements

This report would not be possible without the collaboration of federal, provincial, territorial, and local public health partners. We would also like to thank everyone who took the time to submit an adverse event following immunization report to their local jurisdiction. Ongoing vigilance contributes to ensuring the continued safety of vaccines in Canada.