About COVID-19 Vaccines


COVID-19 vaccines are safe and effective. Health Canada has approved three vaccines for use in Canada. Pfizer-BioNTech was approved on December 9, 2020, Moderna was approved on December 23, 2020, AstraZeneca was approved on February 26, 2021 and Janssen was approved on March 5, 2021. Vaccines are an important tool in our response to the pandemic.

As of May 11th, Ontario paused the administration of first doses of AstraZeneca Vaccine. For more information: Ontario Pauses Administration of AstraZeneca Vaccine | Ontario Newsroom More guidance will be provided in advance of individuals needing to receive their second dose of the AstraZeneca vaccine.

For information about these COVID-19 vaccines, see the following resources:

What you should know about the COVID-19 vaccines (ontario.ca)

Public Health Ontario - What You Need to Know About COVID-19 Vaccine

COVID-19 Pfizer and Moderna About Vaccines (gov.on.ca)

Getting a COVID-19 vaccine in Ontario

Ministry of Health - COVID-19 Vaccine Information Sheet For Youth (ages 12-17)

Ministry of Health - COVID-19 Vaccine Information Sheet



All vaccines work by presenting our body with something that looks like the infection so that our immune system can learn how to produce natural protection. This natural protection then helps to prevent future illness if you come into contact with the COVID-19 virus in the future. You cannot get COVID-19 from the vaccine.

mRNA vaccines (Pfizer-BioNTech and Moderna COVID-19 vaccines) provide our cells with instructions on how to produce a copy of a protein that is found on the surface of the COVID-19 virus. Our bodies recognize this protein which is what starts our immune response. mRNA vaccines are not live vaccines and cannot cause infection in the host. mRNA vaccines also cannot alter a person’s DNA.


Viral vector vaccines (AstraZeneca/COVISHIELD COVID-19 vaccines) Use a genetically modified virus that cannot cause disease, to deliver genetic instructions (DNA) to our cells to produce coronavirus protein that initiates an immune response in the body. Viral vector vaccines cannot cause infection in the host (i.e. they are non-replicating) and cannot alter a person’s DNA.


COVID-19 Vaccines: Viral Vector-based Vaccines (publichealthontario.ca)



About COVID-19 Vaccines (gov.on.ca)

What You Need to Know About COVID-19 Vaccine (publichealthontario.ca)

All COVID-19 vaccines authorized for use in Canada are effective at protecting against symptomatic, lab-confirmed disease. In large studies where people were given both doses of the vaccine, all of the vaccines worked very well to prevent people from becoming sick with symptomatic, lab-confirmed COVID-19. Vaccine efficacy 14 days after dose one and before dose two is estimated to be over 90% for Pfizer-BioNTech and Moderna and over 70% for AstraZeneca/COVISHIELD. Vaccine efficacy after dose two at the recommended interval is estimated to be over 90% for Pfizer-BioNTech and Moderna and over 80% for AstraZeneca/COVISHIELD. It is important that you receive two doses of these vaccines). Long-term protection against COVID-19 is not achieved until after the second dose of vaccine is received. All of the COVID-19 vaccines authorized for use in Canada are also highly effective at preventing hospitalization.

You need two doses of vaccine to be fully immunized. If this is your first dose of the COVID-19 vaccine, be sure to get your second dose as directed by the clinic or the booking system. For information about the extension of the second dose interval see Extended Dose Key Message 2021-03-19 (gov.on.ca).


COVID-19 vaccines are safe. Health Canada only approves a vaccine if it supported by very robust scientific data and evidence.

Learn more about the safety of COVID-19 vaccines, how they work and possible side effects, visit Ontario’s COVID-19 vaccine safety webpage.

Other Resources:

At a Glance: Vaccine Regulatory Process in Canada (publichealthontario.ca)

COVID-19 Vaccine Approval Process and Safety (gov.on.ca)

COVID-19: How vaccines are developed (video) - Canada.ca

Vaccine development and approval in Canada - Canada.ca

COVID-19 vaccines, like all vaccines, may cause side effects, although not everyone experiences them and those who do experience them mostly report minor side effects. The most commonly reported side effects after receiving a COVID-19 vaccine are localized reactions including pain, redness or swelling at the injection site, tiredness, headache, muscle pain, joint pain, chills, and mild fever.

Ongoing studies on these COVID-19 vaccines indicate serious side effects found todate are extremely rare. People who have received the vaccine in these studies continue to be monitored for any longer-term side effects.

Clinic staff are prepared to manage a severe allergic reaction should it occur. When receiving your second dose of COVID-19 vaccine, tell the health care provider administering the second dose if you had any side effects after the first dose.

Very rarely, AstraZeneca/COVISHIELD vaccine has been associated with a rare form of blood clot after vaccination. Doctors are calling this “vaccine-induced prothrombotic immune thrombocytopenia” (VIPIT). These blood clots have two important features: they occur 4 to 20 days after vaccination, and they are associated with low platelets (tiny blood cells that help form blood clots to stop bleeding). VIPIT seems to be rare, occurring in anywhere from 1 in every 125,000 to 1 in 1 million people. It is most common in women under the age of 55. Please see VIPIT Following AstraZeneca COVID-19 Vaccination for more information.

Health Canada has assessed this and determined that the benefits of the AstraZeneca/COVISHIELD vaccine in protecting Canadians from COVID-19 continue to outweigh the risks. Blood clots are common, especially in older people. COVID-19 itself has been associated with causing blood clots, so all COVID-19 vaccines continue to be recommended for people who have had a blood clot in the past, or who have a family history of blood clots and who are receiving blood thinning medications.

Vaccine Side Effects

Vaccine Side Effects - Rash

When they are eligible, vaccines should be offered to individuals without contraindications to the vaccine.

If you have any symptoms that could be due to COVID-19, you should not receive the vaccine at this time. You should also wait 14 days after receiving any other vaccine before receiving the COVID-19 vaccine.

There are special considerations for specific populations including pregnancy, people with autoimmune conditions, people who are immunocompromised and people with severe allergies to vaccine ingredients. If you have questions about if the COVID-19 vaccine is right for you, speak to your health care provider.

Other Resources

SOGC Statement - COVID-19 Vaccination in Pregnancy

COVID-19 Vaccine and Pregnancy Poster

COVID-19 Vaccine Promotion Poster for Healthcare Workers

COVID-19 Vaccination: Special Populations - Vaccination in Pregnancy & Breastfeeding Patient Decision-Making Tool

Youth and COVID-19 Vaccines (publichealthgreybruce.on.ca)

It is your choice. For many people getting a COVID-19 vaccine is the safest choice. Talk to your healthcare provider about the vaccine.

Your health care provider will consider risks of COVID-19 during pregnancy like:

  • An increased risk of ICU admission, need for mechanical ventilation and ventilatory support (ECMO), and death reported in pregnant women with symptomatic COVID-19 infection, when compared with symptomatic non-pregnant women.
  • Pregnant patients with comorbidities such as obesity and diabetes potentially being at an even higher risk of severe illness consistent with the general population with similar comorbidities.

The following resource may also help you when making a decision: COVID-19 Vaccination: Special Populations - Vaccination in Pregnancy & Breastfeeding Patient Decision-Making Tool


Which COVID-19 Vaccine will I be offered?

The National Advisory Committee on Immunization (NACI) recommends that a complete vaccine series with a COVID-19 vaccine (preferably with an mRNA vaccine) be offered to pregnant individuals if a risk assessment deems that the benefits outweigh the potential risks for the individual and the fetus, and if informed consent includes discussion about the evidence of the use of COVID-19 vaccines in this population.

  • mRNA vaccines (Pfizer-BioNTech, Moderna) are preferred for use in pregnant individuals due to recently published data from a study in the United States indicating the mRNA COVID-19 vaccines are safe in pregnant women. In addition, treating Vaccine-induced thrombotic thrombocytopenia (VITT) in pregnant individuals, should it occur following the administration of a viral vector vaccine, is complex. Based on current evidence, VITT does not seem to be associated with the use of mRNA vaccines.
  • Pregnant individuals will be receiving a mRNA COVID-19 Vaccine at Grey Bruce Hub clinics

Planning for your Vaccine during Pregnancy

Pregnant individuals are currently eligible to book their COVID-19 vaccine. Your health care provider can help you plan for when you should receive your vaccine. Please consider:

  • COVID-19 vaccine can be administered in any trimester.
  • It is recommended that individuals wait for 28 days after the administration of the COVID-19 vaccine to get another vaccine. It is also recommended to wait for a period of at least 14 days after the administration of another vaccine, including the flu shot, before getting a COVID-19 vaccine.
  • It is important to consider scheduling the timing of your other vaccines such as the Tdap Vaccine which is important to be administered between the 27th and 36th weeks of pregnancy in order to transfer the greatest number of protective antibodies to your infant.

Is my family member/partner eligible to get a COVID-19 Vaccine as my caregiver during my pregnancy?

  • Maybe. Caregivers are individuals who provide support for those who require regular and sustained assistance with personal care and/or activities of daily living. An essential caregiver is someone providing direct, frequent and sustained in person personal care and/or assistance with activities of daily living to the individual. Consider whether you currently require this level of support due to your pregnancy before booking a caregiver appointment.


Additional Tools and Resources

COVID-19 Vaccination: Special Populations - Vaccination in Pregnancy & Breastfeeding Patient Decision-Making Tool

SOGC Statement - COVID-19 Vaccination in Pregnancy

COVID-19 Vaccine and Pregnancy Poster

COVID-19 and Pregnancy: Information at your Fingertips - Prenatal Screening Ontario (bornontario.ca)

COVID-19 Vaccine and Pregnancy on Vimeo


The vaccine is an additional way to protect yourself against COVID-19. After either dose of the COVID-19 vaccine you should continue to follow COVID-19 measures, such as wearing a mask, practising physical distancing and washing your hands. Continue to monitor for symptoms of COVID-19 and get tested if symptoms present.



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