Eastern Ontatio Health Unit / Bureau de santé de l'Ontario

Frequently Asked Questions About the COVID-19 Vaccine

These are answers to COVID-19 vaccine questions for residents and workers in the Eastern Ontario Health Unit (EOHU) region.

If you wish to speak to a qualified professional about your questions regarding the COVID-19 vaccine, you can Book a VaxFacts appointment at 416-438-2911 ext. 5738 or click here.

General questions about the COVID-19 vaccine:

Questions about COVID-19 vaccine safety:

Questions about how and when the vaccine is being distributed:


General questions about the COVID-19 vaccine

What COVID-19 vaccines are currently approved?

Currently, Health Canada has approved the Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines for use in Canada, as well as the Janssen (Johnson & Johnson), AstraZeneca (COVISHIELD)*, Novavax Nuvaxovid and Medicago Covifenz COVID-19 vaccines. More vaccines may be authorized in the future. For more information on approved COVID-19 vaccines, click here.

Are vaccines interchangeable?

Yes. The Pfizer-BioNTech and the Moderna vaccines can be administered interchangeably (one for the first dose and another for the second, third or fourth) safely, without increased risk or decreased efficacy of the vaccine. They can both also be received safely as a second dose by individuals who received the AstraZeneca/COVISHIELD vaccine for their first dose.

The Provincial Booking System no longer specifies the type of vaccine (Pfizer-BioNTech or Moderna) to be administered when booking an appointment. Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines are administered at COVID-19 vaccination clinics throughout the EOHU region. Depending on vaccine availability at the time of the appointment, individuals attending clinics may not receive the same vaccine they received in previous doses. Rest assured that the best vaccine to receive is the first one that is available to you.

What is an mRNA vaccine?

mRNA vaccines are a new type of vaccine; however, researchers have been studying and working with these vaccines for quite some time. mRNA vaccines teach our cells how to make a protein that will trigger an immune response. Once triggered, our body then makes antibodies. These antibodies help us fight the infection if the real virus does enter our body in the future.

Like all vaccines, people who are vaccinated gain protection without ever having to risk the serious consequences of getting sick from being exposed to the virus. People also can't get COVID-19 from the vaccine itself. mRNA vaccines do not use the live virus that causes COVID-19.

Both the Pfizer-BioNTech and Moderna vaccines are mRNA vaccines.

Is the COVID-19 vaccine mandatory?

The COVID-19 vaccine is not mandatory; however, it is strongly recommended to help protect against the COVID-19 virus, especially for those who are at higher risk of serious illness or death, and for those who work directly with vulnerable people. In addition, some workplaces may have policies that require workers to be vaccinated.

Can I still get or transmit COVID-19 after being vaccinated?

The COVID-19 vaccine is very effective at preventing symptoms in people who get it.

There is a small chance that you may still get COVID-19 after being vaccinated. However, the vaccines are shown to reduce the symptoms and the severity of illness related to COVID-19. As with most vaccines, there is a small chance that cases occur in fully vaccinated individuals, which are called “breakthrough infections.” These occur most commonly among the elderly and other vulnerable people with a lower immune response to vaccines.

However, even in people who experience a breakthrough infection, the vaccines are shown to reduce the symptoms and severity of illness. This in turn reduces transmission because, with most variants, those with a breakthrough infection tend to have a smaller amount of the virus present in their bodies and release less of it while they talk, exhale or do other normal daily activities. It is important to continue taking public health measures such as hand washing and staying home if you are sick.

Why should I get vaccinated if COVID-19 infection has a high survival rate?

COVID-19 can be a serious illness for many people. It is also posible to be re-infected with a different variant of COVID-19 after a COVID-19 infection. Some variants are more transmissible; therefore it is important to stay up to date with COVID-19 vaccination by receiving all doses recommended.

For some people, symptoms can last for months. These people are called long haulers. The virus can even damage the heart, brain and lungs and increase the risk of long-term health problems. Even young, healthy people can feel unwell for weeks to months following the COVID-19 infection.

The short-term side effects of the COVID-19 vaccine are less than the risk and potential long-term health damage caused by the COVID-19 virus.

If I tested positive for COVID-19 in the past, should I still get the vaccine?

Yes. You will have some immunity from your infection, but no one knows how long it will last. There are cases where people have gotten COVID-19 again before they could get vaccinated. You should not get the vaccine if you are sick or have COVID-19 right now. Wait until you are better to get the shot.

Individuals 5 years of age and older, infected* with COVID-19 before completing their primary series, are recommended to receive their next dose 8 weeks after symptom onset or positive test, or 4-8 weeks if moderately to severely immunocompromised with no history of MIS-C, or 90+ days since the onset of MIS-C for any individual 5 years of age and over with a history of MIS-C, regardless of immunocompromised status.

Individuals 12 years of age and older, infected* with COVID-19 after their primary series but before a booster (third or fourth, if eligible) dose, are recommended to receive their booster (third or fourth, if eligible) dose 3 months after symptom onset or positive test (if asymptomatic) and, for 12 to 17 years olds, provided it is at least 6 months from completing the primary series. As per NACI, emerging evidence indicates that a longer interval between SARS-CoV-2 infection and vaccination is associated with improved antibody responses to COVID-19 vaccines.

With informed consent, individuals may receive a booster dose once they are asymptomatic and have completed their isolation. To know more: COVID-19 Vaccine Administration.

*A previous infection with SARS-CoV-2 is defined as a COVID-19 case confirmed by a molecular (e.g., PCR) or rapid antigen test, or symptomatic AND a household contact of a confirmed COVID-19 case.

Are the existing vaccines effective against the new variants of COVID-19?

The vaccines have been shown to be effective against the new variants for individuals who are fully vaccinated with two doses. However, receiving boosters is highly recommended to provide an improved immune response against COVID-19 and its variants.

As with most vaccines, there is a small chance that cases occur in fully vaccinated individuals, which are called “breakthrough infections.” These occur most commonly among the elderly and other vulnerable people with a lower immune response to vaccines. However, even in people who experience a breakthrough infection, the vaccines are shown to reduce the symptoms and severity of illness. This in turn reduces transmission because, with most variants, those with a breakthrough infection tend to have a smaller amount of the virus present in their bodies and release less of it while they talk, exhale or do other normal daily activities.

Why do some populations have a shortened interval between vaccines?

There are some populations who need the additional increase in protection by receiving their COVID-19 dose at a shortened interval. These groups may be at higher risk because they have specific medical conditions, live in a congregate setting with other high-risk individuals (e.g. long-term care homes), or live in communities that are very challenging to reach with medical care.

The National Advisory Committee on Immunization (NACI) recommends that the following populations receive their doses at a shortened interval:

  • Residents of long-term care homes, retirement homes, elder care lodges and assisted living facilities
  • Transplant recipients (including solid organ transplants and hematopoietic stem cell transplants)
  • Individuals with malignant hematologic disorders and non-hematologic malignant solid tumors receiving active treatment (chemotherapy, targeted therapies, immunotherapy), excluding individuals receiving solely hormonal therapy or radiation therapy
  • Individuals undergoing hemodialysis or peritoneal dialysis
  • First Nations and Indigenous populations, and their partners and household members (including non-Indigenous partners and household members) at the interval indicated in the product monograph or when second dose appointments are available for booking

High-risk frontline healthcare workers:

Healthcare workers in the Highest Priority group are also eligible for a shortened interval of the vaccine. Click here for the full list of eligible Highest Priority healthcare workers.

What is considered fully vaccinated?

An individual is considered fully vaccinated 14 days after having received one of the following:

  • The full series of a COVID-19 vaccine authorized by Health Canada, or any combination of such vaccines, or
  • One or two doses of a COVID-19 vaccine not authorized by Health Canada, followed by one dose of a COVID-19 mRNA vaccine authorized by Health Canada, or
  • Three doses of a COVID-19 vaccine not authorized by Health Canada.

However, the protection offered by COVID-19 vaccines decreases over time, requiring the need to receive booster doses. It is therefore highly recommended that individuals stay up to date with their vaccination to maintain a high level of protection against COVID-19.

How do I know if I’m up to date with my COVID-19 vaccines?

While the COVID-19 vaccines authorized by Health Canada all provide a high level of protection against illness and hospitalization from COVID-19, the level of protection they provide decreases over time, especially in older individuals.

This means that receiving a primary series of a COVID-19 vaccine is simply not enough to protect you over time from COVID-19 and its variants like Omicron. It is therefore recommended that individuals stay up to date with their vaccination by receiving all recommended booster doses for which they’re eligible.

Click here for more information about the booster doses you're eligible for, depending on your age, health status, and which vaccines you have received.

Questions about COVID-19 vaccine safety

Is the vaccine safe?

Yes, all vaccines in use in Canada have been approved by Health Canada. Health Canada only approves a vaccine if very robust scientific data and evidence show that it is both safe and effective. After approval, Health Canada and the Public Health Agency of Canada continue to monitor the ongoing safety and effectiveness of all approved vaccines in Canada.

For detailed information on the vaccine and the evidence behind the vaccine approval process, visit the Government of Canada’s website.

What are the most common side effects from the COVID-19 vaccine?

Some people may experience side effects from the vaccine, but these will likely be mild to moderate and resolve after a few days. The most common side effects include pain at the injection site, headache, fatigue, muscle and joint pain, chills and fever.

It is important to receive the second dose and booster doses even if you experience mild or moderate side effects. You may get the same side effects with your second or booster dose.

Are there any serious side effects?

Serious side effects are very rare. They include:

  • Hives
  • Swelling of mouth and throat
  • Trouble breathing, hoarseness or wheezing
  • Fever over 40C or 104F
  • Seizures
  • Very rarely, the AstraZeneca (COVISHIELD) vaccine has been associated with a rare form of blood clotting after vaccination (called vaccine-induced immune thrombotic thrombocytopenia, or VITT). Symptoms include:
    • Shortness of breath
    • Chest pain
    • Leg swelling
    • Persistent abdominal pain
    • Sudden onset of severe or persistent worsening headaches or blurred vision
    • Skin bruising (other than at the site of vaccination)
  • Very rare cases of myocarditis and pericarditis following vaccination with COVID-19 mRNA vaccines have been reported. Symptoms include:
    • Chest pain
    • Shortness of breath
    • Palpitations, or feeling a rapid or abnormal heart rhythm

If you experience serious side effects, you should seek medical help immediately. Do not get a second dose of the vaccine if you have serious side effects following the first dose. Speak to your healthcare provider for advice.

Can I get COVID-19 from the shot?

No. There is no live COVID-19 in the vaccine.

Will the COVID vaccine change my DNA?

No, the vaccine does not and cannot change your DNA in any way.

I am pregnant. Can I get the COVID-19 vaccine?

If you are pregnant, you may choose to receive the COVID-19 vaccine at any time during your pregnancy. It is recommended, but not required, that you have a discussion about the vaccine with your treating healthcare provider, or with a healthcare provider familiar with your pregnancy. However, a letter from a healthcare provider is not required for vaccination.

To help you decide, see this resource from the Provincial Council for Maternal and Child Health.

If you are pregnant and under 18 years old, please contact your primary care provider or call the health unit at 613-933-1375 or 1-800-267-7120 to discuss what is the best option for you.

Who should not get the vaccine?

The following people should not get the COVID-19 vaccine:

  • People who have allergies to the COVID-19 vaccine ingredients should consult their health care provider for an assessment.
  • People who have had a serious allergic reaction to the COVID-19 vaccine (first dose) should not receive a second dose or booster dose of the COVID-19 vaccine until they have been advised by public health.
  • Children under 5 years old are not yet eligible as it has not yet been approved for this age group.
  • Anyone who is sick, has COVID-19, or got a different vaccine in the past two weeks should wait to receive the vaccine.

Right now, people with compromised immune systems or autoimmune disease are strongly encouraged to speak with their treating health care provider regarding timing of vaccination in relation to therapy or treatment for their condition.

For more information, see: COVID-19 Vaccination Recommendations for Special Populations.

If I had a reaction to a different vaccine in the past, can I still get the COVID-19 vaccine?

Check with your doctor or healthcare provider if you have had a serious allergic reaction to a vaccine in the past. They will look at your medical records and help you make the decision.

Should I get the COVID-19 vaccine if I have food or seasonal allergies?

Please talk with your physician or healthcare provider to learn if it is safe for you to receive the COVID-19 vaccine.

I just got vaccinated for something else. Can I still get the COVID-19 vaccine now?

For adults and youth aged 12 and older, the National Advisory Committee on Immunization (NACI) recommends that COVID-19 vaccines may be given at the same time as, or any time before or after, the flu shot or other vaccines, including live, non-live, adjuvanted or unadjuvanted vaccines.

At this time, the recommendations for children aged 5 to 11 are different. NACI recommends that, if possible, children between the ages of 5 and 11 should not receive the COVID-19 vaccine within 14 days of other vaccines. This is a precaution to monitor any side effects from the COVID-19 vaccine or another vaccine. However, in some cases, your child’s healthcare provider may recommend a vaccine that’s needed urgently. This may happen even if your child has received the COVID-19 vaccine in the past 2 weeks.

Should we be concerned about myocarditis and/or pericarditis following a mRNA COVID-19 vaccine?

Cases of myocarditis and/or pericarditis following immunization with COVID-19 vaccines have been reported in a small number of people in Canada and internationally. These reports are very rare and investigations into the association between myocarditis/pericarditis and mRNA vaccines continue.

Health Canada reassures Canadians that COVID-19 vaccines continue to be safe and effective at protecting them against COVID-19. The benefits of COVID-19 vaccines continue to outweigh their potential risks, as scientific evidence shows that they reduce deaths and hospitalizations due to COVID-19. The Government of Canada encourages people to get vaccinated and to complete their vaccine series as soon as they are eligible.

Consult the Advisory: https://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2021/75959a-eng.php


Questions about how and when the vaccine is being distributed

When will I be able to get the COVID-19 vaccine?

COVID-19 vaccines are currently available to all eligible individuals 5 years of age or older. For more information on staying up to date with the COVID-19 vaccines, please refer to: Staying Up to Date with COVID-19 Vaccines: Recommended Doses. Pfizer vaccines have been authorized for individuals aged 5 and older, and Moderna has been authorized for individuals aged 6 older and can be given with informed parental consent.

Third and fourth doses of the COVID-19 vaccine are also currently available. For the latest updates on who is eligible for a booster, see Who is eligible for a third or fourth dose?

Consult the How and Where to Get a COVID-19 Vaccine page for information on vaccination clinic locations and times throughout the EOHU. COVID-19 vaccines are also available at participating pharmacies.

Should I wait for my preferred choice of vaccine?

No. All COVID-19 vaccines that have been approved by Health Canada are effective. It is important to get the vaccine which is recommended for you and for which you are eligible, when it is offered to you – regardless of brand or type.

Who is eligible for a third or fourth dose?

Please see information about Getting a third dose or Getting a fourth dose.

Eastern Ontatio Health Unit / Bureau de santé de l'Ontario