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.

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 available, and how effective are they?

Currently, Health Canada has approved the Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines for use in Canada, as well as the AstraZeneca (COVISHIELD)* vaccine. The Janssen (Johnson & Johnson) vaccine has also been approved but is not yet available in Canada. More vaccines may be authorized in the future.

All COVID-19 vaccines authorized for use in Canada are effective at protecting against illness, hospitalization and death. The Pfizer-BioNTech and Moderna vaccines have been shown to be over 90% effective in clinical trials after the second dose. The AstraZeneca (COVISHIELD) vaccine has been shown over 80% effective after the second dose. All of the COVID-19 vaccines authorized for use in Canada are also highly effective at preventing hospitalization and death.

At this time, vaccine supply is limited and is being prioritized for high-risk population groups and caregivers, with more people having access to vaccination as supply increases over the coming months. (For more information, see Questions about how and when the vaccine is being distributed.)

* NOTE: On May 11th, Ontario announced it is pausing the rollout and administration of first doses of the AstraZeneca vaccine out of an abundance of caution due to an observed increase in a rare blood clotting condition. For information on second doses of AstraZeneca, please see: I received a first dose of the AstraZeneca vaccine, but now it is being paused for first doses in Ontario. What will happen for my second dose?

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) 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 for their second dose may not receive the same vaccine they received as a first dose. 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.

What is the COVID-19 shot like?

The Pfizer-BioNTech, Moderna and AstraZeneca (COVISHIELD)* vaccines are provided in 2 doses by a needle in the upper arm. You should get the first dose as soon as possible. The second dose is given up to 16 weeks after the first dose. It is very important to get both doses. While you have some protection after the first dose, you will have the most protection after getting both doses.

Additional vaccines may be approved for use in the future, which may or may not require a second dose. Instructions will be provided to you at the time of your vaccination.

* NOTE: On May 11th, Ontario announced it is pausing the rollout and administration of first doses of the AstraZeneca vaccine out of an abundance of caution due to an observed increase in a rare blood clotting condition. For information on second doses of AstraZeneca, please see: I received a first dose of the AstraZeneca vaccine, but now it is being paused for first doses in Ontario. What will happen for my second dose?

Is the COVID-19 vaccine mandatory?

The COVID-19 vaccine is not currently mandatory. However, it is strongly recommended for eligible individuals 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.

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. During clinical trials, the Pfizer-BioNTech and Moderna vaccines were shown to be over 90% effective in preventing illness from COVID-19 in individuals who received both doses of the vaccine. The AstraZeneca (COVISHIELD) vaccine was shown to be over 80% effective following both doses.

There is a small chance that you may still get COVID-19 after being vaccinated. It is important to continue taking public health measures such as physical distancing, wearing a mask, and staying home if you are sick.

It is not known if you can still give the infection to someone who has not been immunized if you have been exposed to the virus.

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

COVID-19 can be a serious illness for many people. Among people who are diagnosed with COVID-19 in Canada, about 1 in 13 people require hospitalization, and tragically, about 1 in 40 (~ 2.5%) die.

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.

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

Currently, experts believe the vaccines are effective against the new variants, however this is currently being explored through studies.

Will I need to get the vaccine every year or is it just the two doses?

At this time, the Pfizer-BioNTech, Moderna and AstraZeneca COVID-19 vaccines are only administered in two doses, up to 16 weeks apart.

It is not yet known if the vaccine will need to be repeated in the future, as there is not enough information on the long-term protection provided by the vaccine.

What is the current recommended interval between the first and second dose?

Depending on vaccine supply and appointment availability, the interval between COVID-19 vaccine doses for most Ontarians is 4–16 weeks if your first dose was Pfizer or Moderna, or 8–16 weeks if your first dose was AstraZeneca (see COVID-19 vaccines: getting your second dose for more information).

Some populations require a shorter interval between COVID-19 vaccines doses:

There are special populations who need the additional increase in protection by receiving the second dose at the original recommended interval. These groups may be at higher risk because they have specific medical conditions, live in congregate settings 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 second dose of vaccine according to the original recommended interval (3 weeks for Pfizer, 4 weeks for Moderna, 4 to 12 weeks for AstraZeneca/COVISHIELD):

  • 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 second-dose interval of the vaccine. Click here for the full list of eligible Highest Priority healthcare workers.

What is the reason for extending the interval between the first and second dose of the COVID-19 vaccine?

The extended interval between COVID-19 vaccine doses is based on the National Advisory Committee on Immunization’s (NACI) recommendation to extend the timeline for the second dose of 2-dose vaccines up to 16 weeks for most of the population.

Extending the interval between doses up to 16 weeks will allow us to protect more people by maximizing the number of people who can receive their first dose, and therefore the number of people protected, in the shortest possible time. Evidence suggests that this will reduce infections, symptomatic disease, hospitalizations, and ICU admissions. This means a lot less illness and a lot of lives saved, moving us closer to healthier communities where we can spend time with our loved ones and open our businesses.

NACI’s recommendation to extend dose intervals up to four months to rapidly provide vaccine to as many people as possible is based on:

  • clinical trial evidence that demonstrates very good vaccine efficacy from the first dose;
  • new real-world evidence that suggests good vaccine effectiveness against symptomatic disease and asymptomatic infection and very good effectiveness against hospitalization, including among older populations; there is currently no evidence that this protection decreases over time;
  • mathematical modelling which demonstrates that accelerating vaccine coverage by extending dose intervals would have substantial population-level benefits by reducing symptomatic disease, hospitalizations and deaths while there is limited vaccine supply;
  • principles of vaccine science and immunology, which show that a longer interval between the first and second dose generally results in a better immune response after the second dose;
  • experience with other multi-dose vaccines, which suggests that protection from the first dose of a vaccine series can last six months or longer, while second doses extend protection for even longer;
  • public health principles of ethical decision-making, including equity, feasibility and accessibility, which favours extending intervals, especially while COVID-19 cases, severe illness, hospitalizations, and deaths are high; and in addition, faster progress towards population protection will help to protect vulnerable populations;
  • NACI’s expert opinion that within a global pandemic setting, reducing the risk of severe disease outcomes in the majority of the population and decreasing transmission in the community will have the greatest public health impact.

More information will become available as vaccination programs continue to roll out around the world. NACI will continue to closely monitor the evolving evidence on the effectiveness of an extended dose interval and will update their recommendation as needed.

Will there be enough vaccine for everyone?

Yes. Canada has secured enough vaccines to ensure that a second dose will be available to every adult who wishes to be vaccinated, to ensure completion of the vaccine series.

If I travel outside of the country after receiving the vaccine, do I still need to isolate for 14 days after returning from my trip?

The Government of Canada strongly advises against non-essential travel outside of Canada until further notice. If you do travel outside of Canada, you are required to isolate for 2 weeks immediately upon returning. This requirement remains in effect even if you have had the COVID-19 vaccine. For more information on travel restrictions and requirements, see Travel restrictions, exemptions and advice.


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 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 even if you experience mild or moderate side effects. You may get the same side effects with your second 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)

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.

There have been recent reports of blood clots following vaccination with the AstraZeneca COVID-19 vaccine. Is the AstraZeneca (COVISHIELD) vaccine safe?

Very rarely, the AstraZeneca vaccine has been associated with a rare but serious form of blood clotting after vaccination.

As of May 11th, Ontario announced it is pausing the rollout and administration of first doses of the AstraZeneca vaccine out of an abundance of caution due to an observed increase in the rare blood clotting condition.

On May 21st, the Ontario government, in consultation with the Chief Medical Officer of Health and other public health experts, made the decision to proceed with second dose administration of the AstraZeneca COVID-19 vaccine. This decision was based on the latest science and evidence that suggests that risk of blood clotting is dramatically lower following administration of second doses of AstraZeneca.

I received a first dose of the AstraZeneca vaccine, but now it is being paused for first doses in Ontario. What will happen for my second dose?

The Ontario government has updated its guidance for individuals who received a 1st dose of the AstraZeneca vaccine and who have not yet received a 2nd dose. In alignment with NACI’s recommendation, Ontarians who have received their first dose of the AstraZeneca COVID-19 vaccine can choose to either receive a second dose of the AstraZeneca vaccine, or an mRNA (Pfizer or Moderna) vaccine for their second dose. Both second-dose options for individuals who received their first dose of the AstraZeneca vaccine are safe and provide strong protection against COVID-19 and will count as a completed series.

These second dose options will be provided at a minimum 8-week interval:

  • If you received a 1st dose of AstraZeneca vaccine at least 8 weeks ago and would like to have a 2nd dose of AstraZeneca vaccine, contact the pharmacy or primary care provider where you received your first dose to book an appointment.
  • If you received a 1st dose of the AstraZeneca vaccine at least 8 weeks ago and prefer to receive an mRNA vaccine for your 2nd dose, you can use the provincial booking system (or call 1-833-943-3900) to schedule your 2nd dose appointment at a clinic where the Pfizer or Moderna vaccines are administered. Primary care settings and pharmacies may also be reaching out to eligible residents who received the 1st dose of AstraZeneca vaccine at their clinics. 

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.

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 not be vaccinated. Talk to your doctor or healthcare provider if you are unsure.
  • People who have had a serious allergic reaction to the COVID-19 vaccine (first dose) should not receive a second dose of the COVID-19 vaccine.
  • Children under age 12 should not receive the vaccine at this time, 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, the following people should talk to their healthcare provider to determine if the benefit of being vaccinated outweighs any potential risks:

  • Pregnant women or those trying to get pregnant
  • People who are breastfeeding
  • People with compromised immune systems or autoimmune diseases

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?

You should wait 14 days before receiving the COVID-19 vaccine if you have had another type of vaccine.

After receiving a dose of the COVID-19 vaccine, you should not receive any other vaccines for 28 days. If for some reason you need another vaccine within 28 days, discuss this with your doctor or healthcare provider.

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-1MoH 9 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?

Due to global supply issues, the vaccine is being distributed in stages until enough doses are available from manufacturers to vaccinate everyone who wants the vaccine.

At this time, the EOHU has received a limited supply of COVID-19 vaccines, which are being distributed in accordance with Ontario’s mandated vaccine roll-out plan. For the latest updates on who is scheduled to receive vaccines in the EOHU area, see COVID-19 Vaccine Distribution in the EOHU Region.

Vaccine delivery is expected to accelerate over the coming months. As vaccine stock increases, vaccination will expand to more population groups. It is anticipated that by this fall (or sooner), anyone who wants a vaccine will have access to one.

How will I know when it’s my turn to get the vaccine?

The vaccine schedule will be shared widely with the public and various population groups once it becomes available. For the latest updates on who is scheduled to receive vaccines in the EOHU area, and how information will be shared, see COVID-19 Vaccine Distribution in the EOHU Region.

Why are residents and workers in long-term care and high-risk retirement homes getting the vaccine first?

Residents of long-term care (LTC) and high-risk retirement homes are some of the most vulnerable people in our community, and are at highest risk of serious illness and death from COVID-19. For this reason they are the first priority group for COVID-19 vaccination.

Most residents in these types of homes need assistance with activities of daily living. In order to ensure that they have the help they need, it is vital for workers and essential caregivers in long-term care and retirement homes to remain healthy. Vaccinating workers and essential caregivers against COVID-19 will help protect both them and the residents in their care.

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.

What happens if it’s my turn to have the vaccine, but I wait to get it?

If it is your turn to be vaccinated, it is important to get the vaccine. If you wait, it may take longer to get the vaccine when you want it.

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