Skip to main content

Vaccine Safety

Learn more about how vaccine safety is monitored.

Last updated: November 18, 2021

Health Canada has a thorough approval process that ensures the safety of the many vaccines and medicines we take routinely. This rigorous process is used before any vaccines are approved for use in Canada. Once a vaccine is approved and begins to be used, vaccine safety is continuously monitored to identify any serious adverse events. 

It’s up to you whether you want a COVID-19 vaccination. Feeling worried or hesitant is completely normal when something is new.

Several COVID-19 vaccines being developed use the same technology as vaccines that have already been used successfully for other diseases. 

Approval is happening quickly because Health Canada shortened the administrative and organisational process. The safety approvals have not changed. The requirements for safety data in clinical trials are as stringent as the regular processes.

Learn more about vaccine approvals.
There’s always a small chance of side effects, no matter the drug or vaccine you’re taking. Serious side effects are assessed in clinical trials. Thousands of people have already taken the vaccine through these trials. 

Once the vaccine is approved and begins to be used in a larger population, surveillance and evaluation continue to identify any side effects, commonly referred to as adverse events following immunization, that are less frequent. This is true of all vaccines. 

If these events happen, authorities investigate to identify whether the vaccine is directly responsible for the adverse event. If required, a vaccine can be withdrawn from the market and not used if there is a concern of harm. Health Canada can also issue warnings about specific risks in order to inform individuals.  

The province monitors adverse events following immunization through the immunization surveillance system and reports to the national and global safety surveillance systems. Health Canada also monitors vaccines continuously after roll-out. 

See below for weekly reports of adverse events in B.C.

[click to enlarge]

‎You are likely talking about vaccination with your friends and family. You may have heard stories about people having a reaction or adverse event after getting a vaccine. While sometimes these things can happen after vaccination, it is rarely because of the vaccine. 

Getting vaccinated is important. Given the serious health consequences of COVID-19, the low likelihood of a serious reaction to a vaccine is outweighed by the benefits to you and your loved ones.

Monitoring adverse events in B.C.

This report summarizes adverse events following immunization (AEFI) with COVID-19 vaccines. 

Health care professionals who need to report an adverse event following immunization should refer to this one-page resource on reporting adverse events following immunization

Vaccine safety surveillance is conducted for all vaccines including the COVID-19 vaccines under a regulatory framework in BC. This report summarizes the reports of COVID-19 vaccine adverse events following immunization (AEFI). 

Find national reports on vaccine safety from the Public Health Agency of Canada.

Rare side effects reported following vaccination

B.C., Canada, and many regions around the world have robust systems to monitor vaccine side effects, commonly referred to as adverse events following immunization. This includes the COVID-19 vaccines currently being offered. 

While the side effects we are seeing in B.C. and Canada largely correspond to those identified in the vaccine trials, rare cases of serious blood clots have been reported in individuals after they received the AstraZeneca or COVISHIELD vaccine. 

However, the risk of serious blood clots with the second dose is about 1 in 600,000. This is a rare event and the risk is lower with the second dose than with the first dose, which is about 1 in 50,000.

People in B.C. who received the AstraZeneca or COVISHILED vaccine will have the option to get a second dose of one of these vaccines or to get an mRNA vaccine for a second dose.

Learn more about factors to consider in choosing your second dose vaccine.

Talk with your primary care provider, pharmacist, or call 8-1-1 (HealthLink BC) if you have any questions prior to booking an appointment for your second dose.

If you have already received a COVISHIELD vaccine and have questions about the signs and symptoms of TTS, please refer to Vaccination Aftercare

In rare cases, people have experienced inflammation of the heart following immunization with a COVID-19 mRNA vaccine. Two conditions, called myocarditis and pericarditis, have occurred more often in younger adult and adolescent males and after the second dose. These events have been reported in B.C. at a rate of 1.5 per 100,000 doses of mRNA vaccine administered, and are seen more often after the second dose, and in males under 40 years of age. Most cases will have symptoms within a few days of vaccine receipt.

Typically, this condition after mRNA vaccines has been mild, with sometimes a brief hospital stay. People have recovered with or without treatment. Studies are ongoing to assess whether there are any residual effects. For further information, visit the U.S. Centres of Disease Control.

The exact cause of these events is not known but is thought to be related to the immune response to the spike protein which is also important in immunity against COVID-19 virus. This is considered a safety signal of interest that is being monitored very closely.

These events have been seen internationally, and are being monitored in Canada with regular Public Health Agency of Canada reports here

Symptoms of heart inflammation can include:
  • Chest pain
  • Shortness of breath
  • Feeling of a rapid or abnormal heart rhythm.
If you experience these symptoms, seek medical attention right away. Inform the health care provider that you received a COVID-19 vaccine recently.

The benefits of vaccination continue to outweigh the risks and public health recommends that young people continue to get vaccinated against COVID-19. There are clear and significant benefits from mRNA vaccines in reducing severe disease, hospitalizations and deaths due to COVID-19 infections.

Reporting adverse events

Please report any adverse events to your immunizer, healthcare provider, or doctor following your vaccination. Healthcare providers are trained to report these events to the correct channels to monitor vaccine safety. 

If you have questions about side effects or a possible reaction to the vaccine, contact HealthLinkBC by calling 8-1-1.

It is very rare for a vaccine to result in a permanent injury. Canada’s Vaccine Injury Support Program is a federal program that provides financial support to you if it is determined that you have experienced a serious and permanent injury after receiving a Health Canada-approved vaccine, administered in Canada on or after December 8, 2020. This includes COVID-19 vaccines as well as other vaccines approved by Health Canada. Financial support is also available to dependents of an individual who has died after vaccination. Learn more at

Information about adverse events is not shared between the Vaccine Injury Support Program and B.C.’s immunization program. If you submit a claim to the Vaccine Injury Support Program, please make sure you have also reported any adverse events to a healthcare provider in B.C. so that the event can be reported and vaccine safety can be monitored.

Vaccine choice

All vaccines approved in Canada and available in B.C. are safe and effective and will help protect you against COVID-19. In clinical trials, those who had received a vaccine were significantly less likely to become sick with COVID-19. While some people may still get COVID-19 after they have been vaccinated, all vaccines have been shown to have a high level of protection against serious illness and death. 

The vaccine you are offered is based on a variety of factors including what products are available, your age, health conditions or allergies, where you’re getting your vaccine, and more.

People eligible to get their first or second dose will get either the Pfizer or Moderna vaccine at a mass clinic and do not get a choice between the two. Both vaccines are safe, use comparable mRNA technology, and are similarly effective.

Some pharmacies in B.C. are able to administer a first dose of AstraZeneca to anyone 18 years and older who cannot receive an mRNA vaccine. Find a pharmacy.


Vaccine effectiveness

Learn more about measuring the effectiveness of COVID-19 vaccinations.

SOURCE: Vaccine Safety ( )
Page printed: . Unofficial document if printed. Please refer to SOURCE for latest information.

Copyright © BC Centre for Disease Control. All Rights Reserved.

    Copyright © 2021 Provincial Health Services Authority.