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COVID-19 vaccines – mRNA


​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Immunization protects you from disease.
​​Get protected, get immunized.

  • Vaccines make your immune system stronger. They build antibodies to help prevent diseases.
  • Immunization is safe. It's much safer to get immunized than to get this disease.​​

What are COVID-19 vaccines?

COVID-19 vaccines protect against the SARS-CoV-2 virus (also known as COVID-19). The virus causes an infection in the lungs and airways and is a type of respiratory illness. Go to to learn more about COVID-19.

There are 2 types of COVID-19 vaccines approved for use in Canada:

Who should get an mRNA COVID-19 vaccine?

You should get an mRNA COVID-19 vaccine if you’re age 5 years or older. Everyone is at risk of COVID-19. COVID-19 vaccines are free.

What if my child is getting a COVID-19 vaccine?

Children under age 18 years need a parent or guardian to give consent for them to get a COVID-19 vaccine. If a parent or guardian can’t be at the appointment, they can give consent in writing using the consent form at

In some cases, children under age 18 years may be able to give their own consent.

How well do COVID-19 vaccines work?

If you’re healthy and get all the doses you need, COVID-19 vaccines give you very good protection against COVID-19 infection. Two doses of the mRNA vaccines give more protection than 2 doses of the AstraZeneca/COVISHIELD vaccine of 1 dose or​ the Janssen vaccine. 

All the vaccines work very well to lower your risk of getting seriously ill and of needing to be in the hospital.

Even if you’ve had a COVID-19 vaccine, it’s still important to follow public health measures to prevent the virus from spreading. Go to for the most up-to-date information.

How many doses of mRNA COVID-19 vaccine do I need?

You need at least 2 doses of an mRNA COVID-19 vaccine to be considered fully immunized. These doses are called your primary series.

Some people may need more doses. See the following information and visit to learn more.

Third doses

For some people, 2 doses may not give enough protection. You may need a third dose to complete your primary series if you are age 12 or older and you have a health problem that weakens your immune system. For example:

  • You've had​ or will have an organ or stem cell transplant.
  • You have kidney disease and need dialysis.
  • You have acquired immunodeficiency syndrome (AIDS).
  • You take certain medicines that weaken your immune system.
Booster doses

After your primary series, you should get an extra (booster) dose for more protection if you are age 18 years or older and it has been 5 months or more since your last dose. A booster dose will give you better protection against the Delta and Omicron variants.

Go to​ to book an appointment for your booster dose.

Doses for travel

If you’re travelling outside of Canada and you’ve had only viral vector-based vaccines or different vaccines for your first 2 doses, you may be able to get additional doses. This is only if your destination requires you to have a certain COVID-19 vaccine series.

Can I get an mRNA COVID-19 vaccine if I’m pregnant or breastfeeding?

Yes, you can get an mRNA COVID-19 vaccine if you’re pregnant or breastfeeding. Research shows that mRNA vaccines are the safest type of COVID-19 vaccines to get during pregnancy.

When you’re pregnant, you have a higher risk of getting very sick from COVID-19. Getting a COVID-19 vaccine when you’re pregnant lowers your risk of getting seriously ill from the virus.

If you’re pregnant or breastfeeding and have questions about getting a COVID-19 vaccine, talk to your healthcare provider.

Where can I get a COVID-19 vaccine?

Go to to find out where and when you can get a COVID-19 vaccine.

Are there side effects from mRNA COVID-19 vaccines?

There can be side effects from mRNA COVID-19 vaccines, but they tend to be mild and go away in a few days. Side effects may include:

  • redness, swelling, or feeling sore where you had the needle
  • feeling tired or have a headache
  • a fever or chills
  • body aches or sore joints
  • feeling sick to your stomach (nausea), vomiting (throwing up), or loose stool (diarrhea)
  • swollen lymph nodes
  • a reduced sense of touch or a feeling of numbness
  • feeling dizzy
  • rash or hives

You may be more likely to have these side effects if you have another vaccine at the same time as a COVID-19 vaccine.

Current information shows that there’s a similar risk of side effects after a first, second, or additional dose of COVID-19 vaccine. Research continues to find out more about the risk of side effects after additional doses.

It’s important to stay at the clinic for 15 minutes after your vaccine. Some people may have a rare but serious allergic reaction called anaphylaxis. If anaphylaxis happens, you’ll get medicine to treat the symptoms.

It’s rare to have a serious side effect. Call Health Link at 811 to report any serious or unusual side effects.

What rare events have been reported after getting an mRNA COVID-19 vaccine?

There have been very rare reports of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart) within 7 days of getting either the Pfizer-BioNTech or the Moderna vaccine. The inflammation can cause shortness of breath, chest pain or pressure, or a very fast or abnormal heart rate. Get medical help right away if you have any of these symptoms.

These rare events were reported mostly after the second dose and in young adults and adolescents. They were also reported more commonly in males. Most cases were mild and got better with treatment. Research is still being done to find out more about the risk of these events after a third dose or a booster dose.

The Moderna vaccine has a higher risk of these events than the Pfizer-BioNTech vaccine, especially for those age 12 to 29 years getting their primary series. Because the Moderna vaccine was only recently approved for use in 12- to 17-year-olds, there is more to learn about these risks for this age group after getting the Moderna vaccine.

It is best for those age 12 to 29 years to get the Pfizer-BioNTech vaccine. It has a lower risk of myocarditis and pericarditis in this age group.

In clinical trials with the Pfizer-BioNTech vaccine, there were no reports of myocarditis or pericarditis in children age 5 to 11 years. But because this vaccine was only recently approved for use in this age group, there’s still more to learn about these risks.

Talk to your healthcare provider if you’ve ever had myocarditis or pericarditis and you have questions about COVID-19 vaccines. It’s not yet known if having a history of these health problems puts you at higher risk for these rare events after a COVID-19 vaccine.

Your risk of getting seriously ill from COVID-19 is much higher than your risk of having a rare event after these vaccines.

Go to COVID-19 Vaccine Frequently Asked Questions for more information.

How can I manage side effects?

To help with soreness and swelling, put a cool, wet cloth over the area where you had the needle.

There is medicine to help with a fever or pain. Check with your doctor or pharmacist if you’re not sure what medicine or dose to take. Follow the directions on the package. Children under the age of 18 years should not take aspirin because it can cause serious health problems.

Some people with health problems, such as a weak immune system, must call their doctor if they get a fever. If you’ve been told to do this, call your doctor even if you think the fever is from the vaccine.

What vaccine will I get for my primary series?

Here are the recommended vaccines by age group:

  • Age 5 to 11 years: You will get the Pfizer-BioNTech mRNA vaccine.
  • Age 12 to 17 years: You can get either the Pfizer-BioNTech or Moderna mRNA vaccine.
  • Age 18 years and older: You can get either the Pfizer-BioNTech or Moderna mRNA vaccine. If you can’t get or don’t want an mRNA vaccine, you can get a viral vector-based vaccine.

If you are age 12 to 29 years, it’s best to get the Pfizer-BioNTech vaccine. This vaccine has a lower risk of myocarditis and pericarditis for this age group. 

Usually you get the same vaccine for all your doses. If your first-dose vaccine isn’t available or you can’t have it, you can get a different COVID-19 vaccine for your next dose.

Whichever vaccine you get to complete your primary series protects you against COVID-19.

Go to​ for more information.

What vaccine will I get for my booster or additional dose?

You will get an mRNA vaccine for any booster or additional doses. If you are age 18 to 29 years, it's recommended to get the Pfizer-BioNTech vaccine for your booster dose. There’s more to learn about the risk of myocarditis and pericarditis after getting a booster dose. But with the primary series, we have seen that the Pfizer-BioNTech vaccine has a lower risk of these rare events in those age 12 to 29 years.​

If you can’t get or don’t want an mRNA vaccine, you can get the AstraZeneca/COVISHIELD vaccine.

The Pfizer-BioNtech and Moderna vaccines are licensed for booster doses for people age 18 years or older who get their booster dose no sooner than 6​ months after they've completed their primary series.

In other cases, the vaccine isn’t licensed for more than 2 doses. But vaccine experts support this in certain situations. This is called “off-label use.” 

Getting more than 2 doses of a COVID-19 vaccine is off-label use if:

  • You are age 5 to 17 years.
  • You get a dose sooner than 6 months after you have completed your primary series.
  • You get a viral vector-based​ vaccine as a third dose, booster dose, or additional dose.

Talk to your healthcare provider about which vaccine you can get and when you should have your doses.

What if I had or am getting another type of vaccine?

If you’re age 12 years or older, you can get any vaccine at the same time as, any time before, or any time after a COVID-19 vaccine.

​Children under age 12 years should wait at least 14 days after getting a COVID-19 vaccine before getting another vaccine. If they got another vaccine first, they should wait 14 days before getting a COVID-19 vaccine. This helps you watch for any side effects from the COVID-19 vaccine. However, if your child needs another vaccine on the same day or within 14 days before or after the COVID-19 vaccine, there are no safety concerns. Both vaccines will still work to protect your child. This may happen if your child is due to have a routine school immunization within 14 days of having the COVID-19 vaccine. Talk to your healthcare provider if you have questions about your child’s vaccine schedule.

Who should not get an mRNA COVID-19 vaccine?

You may not be able to get an mRNA COVID-19 vaccine if you:

  • have an allergy to any part of the vaccine
  • had a severe (serious) or unusual side effect after this vaccine or one like it
  • are under age 5 years

Check with your doctor or a public health nurse before you get an mRNA COVID-19 vaccine.

Be sure to talk to your doctor before you get an mRNA COVID-19 vaccine, if you:

  • have a weak immune system (because of a medicine you take or a health problem)
  • have an autoimmune disorder (like rheumatoid arthritis or lupus)
  • have had a stem cell or organ transplant
  • have a history of myocarditis or pericarditis after receiving a dose of COVID-19 vaccine
  • have been treated for a COVID-19 infection in the last 90 days
  • are under age 12 years and have a history of multisystem inflammatory syndrome (MIS-C)

Always tell your healthcare provider if you have allergies or if you've had a side effect from a vaccine in the past.

Facts about COVID-19

What is COVID-19?

COVID-19 is a new strain of coronavirus that’s caused a worldwide pandemic. The virus causes an infection in the lungs and airways and is a type of respiratory illness. Symptoms may include:

  • a fever
  • a cough
  • shortness of breath or trouble breathing
  • a sore throat
  • a runny or stuffy nose
  • loss of sense of smell or taste

Most people have only mild symptoms or no symptoms at all. But if you’re an older adult or have other health problems, you can get very sick and may need care in a hospital. In serious cases, COVID-19 can cause a type of lung infection called pneumonia. Pneumonia makes it hard to breathe without help and can even lead to death.

Go to COVID-19: How to manage symptoms​ for a list of all symptoms that may be related to COVID-19.

How does it spread?

COVID-19 spreads:

  • when an infected person sneezes, coughs, or talks
  • if you breathe in the virus
  • if you touch something that has the virus on it (like hands or a doorknob) then touch your eyes, mouth, or nose

It’s important to know that you and others can spread COVID-19 before symptoms start.

Go to to find out more.

How can I prevent COVID-19 from spreading?

To prevent COVID-19 from spreading:

  • get immunized
  • wash your hands with warm water and soap or use an alcohol-based hand sanitizer often
  • don’t touch your face, nose, or mouth with unwashed hands
  • cover your cough or sneeze into your arm or a tissue, not your hand
  • stay home when you’re sick
  • avoid close contact with people who are sick

If you think you’ve had contact with COVID-19 or have symptoms, take the COVID-19 Self-Assessment at

More information

Current as of: January 10, 2022

Author: Provincial Immunization Program, Alberta Health Services