FAQ COVID-19 vaccine for children

Questions and answers for parents and legal guardians regarding the pediatric Pfizer-BioNTech Comirnaty COVID-19 vaccine for children aged 5-11

On this page:


Additional information

Q. Why should my child be vaccinated for COVID-19?

Vaccination is important for children. With variants of concern emerging like the Delta variant, we are seeing increasing cases of COVID-19 in children in New Brunswick. Approximately 30 per cent of cases reported since Sept. 1, 2021 are among youth under 20. Vaccination against COVID also reduces the spread in the community for individuals who are at risk of severe COVID (the elderly, immune-compromised individuals, and individuals who cannot be vaccinated).  It also helps stop the spread of other variants of concern from changing into another more infectious variant.

While some of the cases in children affected with COVID-19 are mild and asymptomatic, some children get very sick, end up hospitalized and in rare cases can even die. Long-term COVID-19 complications or symptoms (ex: chronic fatigue, shortness of breath, difficulty concentrating) can last for months after the infection and people who experience these effects are commonly nicknamed as COVID-19 “long-haulers.”

Another rare complication involving persistent fever and extreme inflammation following exposure to COVID-19 is called Multisystem inflammatory syndrome in children (MIS-C). In children who go on to develop MIS-C, some organs and tissues (ex: heart, lungs, blood vessels, kidneys, digestive system, brain, skin or eyes) become severely inflamed. Signs and symptoms depend on which areas of the body are affected.

Vaccinated children will help to reduce the number of cases of COVID-19 in our community and help protect them and your family.

Q.  Is the Pfizer-BioNTech Comirnaty COVID-19 vaccine safe for my child?

Yes, the vaccine is safe. Approved vaccines have met Health Canada’s strict standards. Health Canada's independent drug review process is recognized around the world for its high standards and rigor. Its decisions are based only on scientific and medical evidence showing that vaccines are safe and effective. The benefits must also outweigh any risks.

Canada also has a national vaccine safety network that rapidly shares information on emerging safety issues to enable effective public health response.

Find detailed technical information such as the product monograph and the regulatory decision summary: Pfizer-BioNTech Comirnaty® vaccine regulatory information.

Q. What are the common side effects of the vaccine?

Children typically experience mild to moderate side effects that are similar in nature to those experienced by adults. Side effects should only last a few days. Clinical trials of the vaccine showed no serious side effects. Most side effects are easy to manage with rest. Some of the following symptoms may occur after your child’s vaccination:

Fatigue: Your child may feel generally uncomfortable, sick and miserable. The best remedy for these side effects is rest. This might be a good time to read a good book with them or a watch a movie.

Aching muscles and joints: An achy body can also be treated with rest. Avoid strenuous activity until symptoms improve.

Headaches: Pain in or around the head and neck can make anyone feel irritable, especially children. A cool or warm washcloth on your child’s forehead or neck can help a headache. Dimming the lights and avoiding screen time may also help. Ensure your child is well hydrated and encourage regular sips of water.

Injection site discomfort: The injection site area can be sore, red or even a little swollen for a few days. A cool washcloth or over the counter acetaminophen can help ease the pain.

Chills or fever: For low grade fever, encourage your child to wear lighter clothing. Fever-reducing medications such as acetaminophen or ibuprofen may be used with the advice of your health-care provider.

Aspirin (ASA) should NOT be given to children under 18 years of age because of its link to Reye's syndrome.

Q. What are the rare side effects of the vaccine?

As with all vaccines, there's a small chance of a serious allergic reaction to a vaccine. It is important for your child to stay 15-30 minutes after vaccination so health-care providers can watch for abnormal or very rare reactions (like anaphylaxis) and treat them quickly.

The risk of myocarditis/pericarditis (inflammation of the heart or the lining on the outside of the heart) in children following immunization with the 10-mcg pediatric dose of the Pfizer-BioNTech Comirnaty COVID-19 vaccine is unknown. Safety surveillance data from individuals aged 12 and older does not suggest the risk of myocarditis/pericarditis following mRNA COVID-19 vaccination would be greater in children aged five to 11 compared to older populations.

This may be mitigated by the reduced vaccine dose (10 mcg vs 30 mcg).

Severe allergic reactions usually occur shortly after a person has received the vaccine and can be treated. That's why it's important to stay at the vaccination site for 15 to 30 minutes after an injection, so that health-care providers can monitor these abnormal or very rare reactions (such as anaphylaxis) and treat them quickly. Signs and symptoms of anaphylaxis may include:

  • urticaria (hives that appear on the skin that usually itch a lot);
  • swelling of the lips, face, tongue or respiratory tract;
  • difficulty breathing;
  • increased heart rate;
  • loss of consciousness;
  • sudden drop in blood pressure;
  • abdominal pain, vomiting and diarrhoea.

Approved vaccines have met Health Canada’s strict standards. Health Canada's independent drug review process is recognized around the world for its high standards and rigor. Very rare side effect reports continue to be monitored closely by:

  • Public Health New-Brunswick and the Department of Health’s Surveillance team
  • Vaccine Vigilance Working Group
  • Public Health Agency of Canada
  • Manufacturers: Pfizer
  • The World Health Organization

Q. How was the Pfizer-BioNTech Comirnaty COVID-19 vaccine for children tested?

mRNA COVID-19 vaccines were tested in children and youth through clinical trials that compared the safety and effectiveness of the vaccine to a placebo (a “fake” vaccine). They also compared safety and effectiveness across different age groups. These studies:

  • confirm the vaccines are safe for use in children and youth aged 5 to 17; and
  • determine what doses are most effective for different age groups.

In phase 3 clinical trials, the vaccines were very effective at preventing COVID-19 with symptoms in youth aged five to 17. Vaccine manufacturers will continue to collect information about safety from clinical trial participants. Canada’s vaccine safety monitoring system will also help to detect any possible rare side effects that didn’t appear in the clinical trials.

Learn more about:

Q. I am worried the mRNA vaccine technology was rushed. Were steps skipped in making the vaccine?

Vaccine developers did not skip any steps. There was a lot of teamwork from scientists around the world to work on the various steps and gather scientific data at the same time. A global collaboration means the vaccines were developed in a timelier matter as part of the global effort to end the COVID-19 pandemic.

mRNA vaccines can be made faster than traditional methods because they're made in a lab using materials that are easily available. Once developed, large-scale clinical trials are carried out to show that the vaccine is safe and effective.

Q. Is the mRNA vaccine technology new?

mRNA vaccine technology is not entirely new. Although the COVID-19 vaccines made by Pfizer-BioNTech are the first mRNA vaccines to complete all clinical trial stages and be licensed for use, the technology has been around for a while.

Researchers have been studying and working with mRNA vaccines for decades. For example, they've been studied for use in flu, Zika, rabies and cytomegalovirus (CMV). Researchers have also used mRNA to trigger the immune system to target certain cancer cells and the technology has been used in human cancer vaccine trials since 2011.

Q. How does the mRNA vaccine work?

Explained in general:

Vaccines work with your immune system, so your body will be ready to fight the virus if you are exposed. Messenger ribonucleic acid (mRNA) vaccines don't use live virus to trigger an immune response. Instead, they teach your cells how to make a protein that will trigger an immune response. The mRNA molecule is essentially a recipe, telling the cells of the body how to make the spike protein.

Explained in more details:

The messenger ribonucleic acid (mRNA) is a molecule that provides cells with instructions for making proteins. mRNA vaccines contain the instructions for making the SARS-CoV-2 spike protein. This protein is found on the surface of the virus that causes COVID-19.

After the protein piece is made, the cell breaks down the instructions and gets rid of them. The mRNA never enters the middle part (nucleus) of the cell, which is where our DNA (genetic material) is found.

The cell then displays the protein piece on its surface. Our immune system recognizes that the protein doesn't belong there and begins building an immune response and making antibodies. Once triggered, your body makes antibodies. These antibodies help you fight the infection if the real virus does enter your body in the future.

Q.  Will the mRNA change the DNA of my child?

Some parents may have heard false information that the mRNA vaccines could change their child’s DNA. That idea has no scientific basis. The mRNA vaccine will not enter the nucleus of the cells, where our DNA is located.

Once the injected mRNA enters a human cell, it dissolves quickly and only stays in the body for a couple of days. mRNA vaccines are designed to only trigger an immune response to the COVID-19 virus's spike protein, which is just one component of the virus’s outer shell.  

Q. My child is four but will be five before Dec. 31, 2021. Can they get the vaccine?

Children born between 2010 and 2016 are eligible to receive the pediatric Pfizer-BioNTech Comirnaty COVID-19 vaccine. This includes four-year-old children who are turning five by Dec. 31, 2021. Beginning January 1, 2022, children must be five years old at the time of vaccination.

Q. My child is 11 turning 12 in 2021 and has had one dose of the adult vaccine. What vaccine will they get for their second dose?

Children who receive the 10 mcg pediatric Pfizer-BioNTech Comirnaty COVID-19 vaccine for their first dose and who have turned 12 years of age by the time the second dose is due may receive the 30 mcg adult Pfizer-BioNTech Comirnaty COVID-19 vaccine that is authorized for individuals aged 12 and older to complete their primary series. If the second dose of 10 mcg is given, the dose will still be considered valid and the series complete.

Q. What is the dosage for children and what interval is needed for their full protection against COVID-19?

This vaccine requires two doses for maximum protection. New Brunswick is following the National Advisory Council on Immunization’s recommendations that children aged five to 11 receive their second dose of vaccine at least eight weeks after receiving their first dose to promote optimal protection.

  • 5-to-11-year-old children: the dosage is 10 micrograms. The injectable volume is 0.2ml delivered into the deltoid muscle of the shoulder.
  • 12 and older: The dosage is 30 micrograms. The injectable volume is 0.3 ml delivered into the deltoid muscle of the shoulder.

Q. My child is turning 12 in a couple of months. Should I wait for the adult dose?

No, because the Pfizer-BioNTech Comirnaty COVID-19 vaccine is just as effective at the 10-microgram dose for kids aged five to 11 as the 30-microgram dose is for older kids and adults.

There’s no reason to wait to get the adult dose. Your child is not going to get stronger protection waiting for a few extra weeks with a higher dose, and delaying vaccinations means your child is unprotected longer.

Q. Since this is a smaller dose, is it less effective for children?

The vaccine is just as effective as the adult vaccine. One goal of vaccines developed for any age is to find the smallest level of antigen (the part that triggers an immune response) to maximize protection without side effects. For some vaccines, adult and child doses can be the same, but in other cases, like with the hepatitis A vaccine, adults get a higher dose than children.  In clinical trials, Pfizer-BioNTech determined they were able to use a lower dose in children and could still get the same immune response and effectiveness as the adult immune response.

Q. How effective is the vaccine for my child?

Clinical trials showed that beginning one week after the second dose, the Pfizer-BioNTech Comirnaty COVID-19 vaccine was approximately:

  • 90.7 per cent effective for children 5-11
  • 100 per cent effective for youth 12 to 15 years
  • 95 per cent effective for those 16 years and older

Q. Does my child really need to get the second dose of vaccine or will they still be protected by just getting the first dose?

Vaccines that need more than one dose aren’t uncommon. Some examples of other vaccines that are part of a multi-dose series include: the measle-mumps-rubella (MMR) vaccine, and vaccines against hepatitis A and hepatitis B. Researchers found that the Pfizer-BioNTech Comirnaty COVID-19 vaccine provokes a relatively weak immune response when given as just one dose. However, there was a stronger immune response when a second dose was added.

Basically, the first dose of the vaccine starts the process of building up protection. The second dose works to greatly reinforce this protection.  For maximum protection against COVID-19 disease, two doses are recommended.

Q. What does “mRNA” in mRNA vaccines mean?

The messenger ribonucleic acid (called mRNA) is a molecule that provides cells with instructions for making proteins.

Q. My child does not like needles. How can I make this experience easier?

Many people dislike needles but there are ways to make it easier, like bringing your child’s favourite toy or distraction such as a phone or a book to keep their mind off getting the needle.

You can help reduce the pain of needle pokes by applying a topical anaesthetic (numbing cream or gel) to the area where the needle will be inserted. This can be purchased from your local pharmacy and you do not need a prescription from your health-care provider to buy it. Apply the numbing cream or gel 30 to 60 minutes before the needle poke. It is important to read and follow the package instructions carefully before using these products on your child. Creams or patches need to be applied prior to the immunization visit because the product needs time to numb the skin once it is applied. Apply the numbing cream or gel 30 to 60 minutes before the appointment. If you remove the product before your appointment, outline the edges of the patch or bandage covering the cream with a pen. This will show your health care provider where the numbing cream or patch was applied. For more information, ask your local pharmacist or health-care provider.

When you call or book your appointment, let staff know your child has anxiety about getting a needle and they will make sure you and your child have the support you need when you arrive. See the following strategies to help you prepare for your appointment:

  • CARDS” (Comfort, Ask, Relax, Distract) strategy to support your child before, during, and after the visit.
  • Talk to your child before the visit about what to expect.
  • Comfort your child during the appointment.

You can book your child’s vaccine online at COVID-19 vaccines (gnb.ca) or by calling 1-833-437-1424

Q. My child has an egg or a nut allergy. Can they still get the COVID-19 vaccine?

This vaccine does not contain common food allergens, such as eggs, shellfish, gluten or nuts. It is safe for your child to get the vaccine.

Q. Will my child be protected for life after two doses, or will they need to get another dose every year?

At this time, it is unknown if children and youth will need additional doses.

Q. Is the dosage for children different than the adult dosage?

Yes. The dose for children is one-third of the adult/youth dose. The vaccine is delivered through a needle in the upper arm and will require two doses. Each dose is 10 micrograms with a volume of 0.2 mL, compared with the 30-microgram dose with a volume of 0.3 mL given to those 12 and older.

If this is your child’s first dose of a COVID-19 vaccine, you will be provided with an appointment to return for their second dose.


Q. Are there any differences between the pediatric vaccine ingredients and the adult vaccine ingredients?

Yes. While no changes have been made to the raw materials, lipids, or manufacturing process and nano particles, a different buffer was used to increase the stability of the product in the pediatric formulation. The buffering agent called Tromethamine (trometamol or Tris) is a sugar that has been used in many vaccines and helps maintain the pH and stability of the product (i.e.: be able to stay in the fridge longer at 2-8 degrees Celsius). It is also one of the ingredients used in the Moderna Spikevax vaccine.

Tromethamine (trometamol or Tris) and is identified as a potential allergen (i.e.: a substance that causes an allergic reaction) and commonly used in over-the-counter products. Another potential allergen in both the pediatric and adult Pfizer-BioNTech Comirnaty COVID-19 vaccine is Polyethylene glycol (PEG).


Vaccine product
Potential allergen included in the vaccine 
Other products where the potential allergenmay be found 

Pfizer-BionTech Comirnaty COVID-19 vaccine for ages 5-11

Polyethylene glycol (PEG)  Over the counter (e.g., cough syrup, laxatives), and prescription medications, medical bowel preparation products for colonoscopy, skin care products, dermal fillers, cosmetics, contact lenscare solutions, products such as ultrasound gel 

Tromethaminee (trometamol or


Contrast media, oral and parenteral medications


Q. What are the specific ingredients in the vaccine?

Detailed information of how those ingredients each play their part in the vaccine can be found here: Components of COVID-19 vaccines authorized by Health Canada - Canada.ca



Pfizer-BioNTech Comirnaty COVID-19 vaccine ingredients pediatric versus adult 




Medicinal ingredient:

  • mRNA


Non-active ingredients pediatric formulation:

  • ALC-0315 = ((4-hydroxybutyl) azanediyl)bis (hexane-6,1-diyl)bis(2-hexyldecanoate)
  • ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide
  • 1,2-distearoyl-sn-glycero-3-phosphocholine
  • cholesterol
  • sodium chloride
  • sucrose
  • tromethamine
  • tromethamine hydrochloride
  • water for injection

Medicinal ingredient:

  • mRNA


Non-active ingredients youth -adult  formulation:

  • ALC-0315 = ((4-hydroxybutyl)azanediyl)bis(hexane-6, 1-diyl)bis(2-hexyldecanoate)
  • ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide
  • 1,2-Distearoyl-sn-glycero-3-phosphocholine
  • Cholesterol
  • dibasic sodium phosphate dihydrate
  • monobasic potassium phosphate
  • potassium chloride
  • sodium chloride
  • sucrose 
  • water for injection

Q. Why was the name of the vaccine changed to “Comirnaty”?

The Pfizer-BioNTech Cormirnaty COVID-19 vaccine is manufactured by Pfizer Canada and BioNTech Manufacturing. The vaccine was authorized for use in Canada under the interim order respecting the importation, sale and advertising of drugs for use in relation to COVID-19. The interim order expired on Sept. 16, 2021. On this date, Pfizer-BioNTech Comirnaty transitioned to an authorization under the Food and Drug Regulations.

Q. Are there long-term side effects caused by mRNA COVID-19 vaccines? How do we know?

The medical and scientific community is confident in the long-term safety of the mRNA COVID-19 vaccines. Researchers have been studying and working with mRNA vaccines for decades. Also see the question: “Is the “mRNA” vaccine technology new?”[WC(1]

The vaccine is not expected to have long-term negative effects for a few reasons:

  • First, most negative effects occur within six weeks of receiving a vaccine, which is why vaccine companies need to provide eight weeks of safety data after the last dose given in clinical trials.
  • Second, the mRNA in the vaccine breaks down quickly because our cells need a way to stop mRNA from making too many proteins or too much protein.
  • Third, even if for some reason our cells did not break down the vaccine mRNA, the mRNA stops making the protein within about a week, regardless of the body’s immune response to the protein.

In addition, the medical and scientific community is confident in the vaccine’s long-term safety, because of the track record of Canada's vaccine approval and safety monitoring system. Overall, this means that the end data and safety tests are exactly the same as other vaccines that have been approved in Canada.

Canada’s system has proven time and again that the data necessary to get through the approval process is sufficient to prove safety, including for the long-term.

Q. Can my child get the flu vaccine or other vaccines at the same time as the Pfizer-BioNTech Comirnaty COVID-19 vaccine?

COVID-19 vaccines for children aged five to 11 should not routinely be given concomitantly (i.e., same day) with other vaccines (live or non-live).

In the absence of evidence, it would be prudent to wait for a period of at least 14 days BEFORE or AFTER the administration of another vaccine before administrating a COVID-19 vaccine to prevent erroneous attribution of an adverse effect following immunization to one particular vaccine or the other.

This suggested minimum waiting period between vaccines is precautionary at this time and will be revisited in the future. A similar approach was taken when the COVID-19 vaccine was first introduced for the adult population.

Q. What other trusted resources and links can I read on COVID-19 vaccines for children?

Additional information from trusted sources include: