Home > AstraZeneca COVID Vaccine

If you are a Quest CHC client and eligible for the AstraZeneca COVID Vaccine you will be contacted to schedule an appointment to receive the COVID Vaccine. We are working closely with public health to ensure all of our client are vaccinated as the vaccine roll-out continues.

AstraZeneca COVID-19 vaccine: What you should know

About the AstraZeneca COVID-19 vaccine

The AstraZeneca COVID-19 vaccine (ChAdOx1-S) is used to prevent COVID-19. This disease is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Canada has authorized 2 manufacturers of the ChAdOx1-S vaccine:

  • AstraZeneca (brand name AstraZeneca COVID-19 Vaccine)
  • Verity Pharmaceuticals and Serum Institute of India (SII) in collaboration with AstraZeneca (brand name COVISHIELD Vaccine)

AstraZeneca COVID‐19 Vaccine (manufactured by AstraZeneca) and COVISHIELD (manufactured by Serum Institute of India) are ChAdOx1-S recombinant vaccines developed by AstraZeneca and Oxford University. Health Canada has reviewed the manufacturing information for these vaccines and found them to be comparable.

The vaccine is approved for people who are 18 years of age and older. Its safety and effectiveness in people younger than 18 years of age have not yet been established.

Health Canada authorized both applications for this vaccine with conditions on February 26, 2021, under the interim order respecting the importation, sale and advertising of drugs for use in relation to COVID-19.

Find detailed technical information about the AstraZeneca vaccine, such as the product monograph and our regulatory decision summary, in the COVID-19 vaccines and treatments regulatory portal.

  • Medicinal ingredient
    • Adenovirus vector vaccine
  • Non-medicinal ingredients
    • disodium edetate dihydrate (EDTA)
    • ethanol
    • L-histidine
    • L-histidine hydrochloride monohydrate
    • magnesium chloride hexahydrate
    • polysorbate 80
    • sodium chloride
    • sucrose
    • water for injection
How it works

Viral vector-based vaccines use a harmless virus, such as an adenovirus, as a delivery system. This “vector” virus is not the virus that causes COVID-19. Adenoviruses are among the viruses that can cause the common cold. There are many different types of adenoviruses, and many have been used as delivery systems for other vector-based vaccines for decades.

When a person is given the vaccine, the vector virus contained within the vaccine produces the SARS-CoV-2 spike protein. This protein is found on the surface of the virus that causes COVID-19. This protein will not make you sick. It does its job and goes away.

Through this process, the body is able to build a strong immune response against the spike protein without exposing you to the virus that causes COVID-19.

How it’s given

The vaccine is given by 2 separate injections of 0.5 mL each into the muscle of the arm. For the vaccine to work best, you need to get 2 doses: a first dose and then a second dose 16 weeks later based on recommendations.

Immunity develops over time. It takes about 2 weeks to develop significant protection against COVID-19. For the greatest protection, you will need the second dose.  

The AstraZeneca COVID-19 vaccine showed an effectiveness of about 62% in preventing symptomatic COVID-19 disease beginning 2 weeks after the second dose. This effectiveness rate is based on an analysis of results from participants who had received the 2 dose regimen that will be used in Canada.

Possible side effects

Health Canada confirms that the benefits of the AstraZeneca COVID-19 Vaccine and COVISHIELD in protecting Canadians from COVID-19 continue to outweigh the risks, and encourages Canadians to get immunized with any of the COVID-19 vaccines that are authorized and available in Canada.

In general, the side effects observed during the clinical trials are similar to what you might have with other vaccines.

The side effects that followed vaccine administration in clinical trials were mild or moderate. They included things like pain at the site of injection, body chills, feeling tired and feeling feverish.

These are common side effects of vaccines and do not pose a risk to health.

As with all vaccines, there’s a chance that there will be a serious side effect, but these are rare. A serious side effect might be something like an allergic reaction. Speak with your health professional about any serious allergies or other health conditions you may have before you receive this vaccine.

In rare cases, individuals experienced blood clots after receiving the AstraZeneca vaccine. Blood clots that may be seen 7-14 days post vaccination. Individuals who experience severe headache or suddenly blurry vision, severe persistent abdominal pain, calf pain and swelling, shortness of breath, and/or chest pain should go to the Emergency Room.

Health Canada has done a review of all the evidence and has deemed that the benefits of vaccination continue to outweigh the risk of this complication. To be cautious, they are recommending women under 55 do not receive this type of vaccine.

For more information:

Health Canada

Ministry of Health Ontario

Ontario College of Family Physicians

Niagara Region Public Health

Source: Health Canada