COVID-19 vaccine information for children ages 6 months to 4 years

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Key points:

  • COVID-19 vaccines are safe and provide good protection against severe illness and hospitalization due to COVID-19.
  • Most children with COVID-19 have mild disease or no symptoms at all; however, some children get severe disease and need to be hospitalized. 
  • Young children get a smaller dose of the same Moderna vaccine used for youth and adults. 
  • Side effects of COVID-19 vaccines are usually mild. Serious side effects are very rare.
  • It is much safer to get the vaccine than to get COVID-19.


You need to register your child with the provincial Get Vaccinated system to get an invitation to book your child's appointment. 


Why should my young child get the COVID-19 vaccine?

Vaccination helps keep children safe and is the best way to protect children from severe illness and hospitalization due to COVID-19. There has been an increase in hospital and ICU admissions in young children since Omicron became the most common variant. 
While most children who get COVID-19 have a minor illness, some children (including previously healthy children) can get very sick. The chance of getting very sick is higher for children who are not fully vaccinated or have certain medical conditions.
Children who get COVID-19:
  • Can get a severe lung infection and heart issues like myocarditis (inflammation of the heart muscle). Myocarditis can occur when a virus, such as the common cold, influenza (flu) or SARS-CoV-2 (the virus that causes COVID-19) infects the body.
  • Are at risk of developing a serious but rare condition called multisystem inflammatory syndrome in children (MIS-C). MIS-C is caused by an exaggerated immune response, leading to severe widespread inflammation. It can happen several weeks after infection and usually requires hospitalization. Most children in Canada who have had this condition have fully recovered with treatment. 
  • While the evidence is limited in children younger than 5, COVID-19 infection may lead to post-COVID condition or "long COVID." This is where people feel sick for weeks or months after the initial illness.
Vaccinating children can also help protect others, including family members and those most at risk. Vaccination can also make it less likely that children will miss out on important activities, like daycare, preschool, sports, and social events.


How many doses of vaccine does my child need?

Children 6 months to 4 years of age need 2 doses of the Moderna vaccine to complete their primary (initial) series. The second dose is offered about 8 weeks after the first. 

Children who are moderately to severely immunocompromised need 3 doses to complete their primary series. These children can get their second dose 4 to 8 weeks after the first. To book your child's third dose, you will be contacted by the provincial Get Vaccinated system about 4 weeks after they receive their second dose. 

Scientists are still determining if children 6 months to 4 years of age will need a booster dose of the COVID-19 vaccine.


What is the dosage for young children? 

Young children get a smaller dose of the same vaccine used for youth and adults. Children aged 6 months to 4 years of age receive a 25 microgram dose, which is a quarter of the dose adults get. Young children need a smaller dose of the vaccine to get the same protection from COVID-19.


Should my child get vaccinated if they have already had COVID-19?

Even if your child already had COVID-19 and recovered, they should still get vaccinated. Previous infection provides some protection but studies in adults show that vaccination following infection provides stronger and longer-lasting protection. If your child was recently sick, they can get the vaccine once they are better, or they can delay getting the vaccine until 8 weeks after their symptoms started or they tested positive for COVID-19.


Is the COVID-19 vaccine safe for young children?

Yes, it is safe. Data from the clinical trial show that the Moderna COVID-19 vaccine (25 mcg dose) is safe for children 6 months to 4 years of age. Health Canada has carefully reviewed the clinical trial data and has determined that the benefits of the vaccine for children in this age group outweigh the potential risks.
While this vaccine was just approved in young children, millions of COVID-19 mRNA vaccines at higher doses have been safely given to people 5 years of age and older in Canada and around the world. Because the dose for young children is lower, it would be unlikely that we would see any new side effects. 
There is a very strict process to test and approve vaccines in Canada. Health Canada only approves a vaccine if the data from clinical trials show the vaccine is safe and effective and that the vaccine's benefits outweigh any risks. Once a vaccine is approved for use, its safety is continuously monitored. 


What are the side effects of COVID-19 vaccines in young children? 

Side effects are normal and are the result of the immune system responding to the vaccine. Some people have no side effects following COVID-19 vaccination, while others may have some type of side effect. Side effects are most often mild and go away by themselves within hours or days. Serious side effects are very rare.  
COVID-19 vaccine side effects in young children are similar to those in older age groups. Common vaccine side effects may include:
  • Redness, soreness, and swelling at the injection site.
  • More general symptoms such as chills, fatigue, joint pain, headache, mild fever, and muscle aches. 
Young children may seem fussy or tired after COVID-19 vaccination, similar to what they experience after other routine vaccines.
No serious side effects, like myocarditis, or other safety concerns were identified in the clinical trial. However, due to the size of the trial (4,792 participants randomized to receive the vaccine), it is unlikely that rare or very rare side effects would have been detected. Health Canada will continue to closely monitor this vaccine as it is used for potential rare and very rare side effects and will take action if any safety concerns are identified.
Rare cases of inflammation of the heart (myocarditis and pericarditis) have been reported after vaccination with COVID-19 mRNA vaccines in older age groups and is likely due to an exaggerated immune response. The rate of cases in younger children is much lower. In the US, this occurred at a rate of about 2.7 cases per 1,000,000 doses of Pfizer vaccine in males 5-11 years of age. Rates for children 6 months to less than 5 years of age are unknown at this time but it is expected that cases will be very rare and rates will be lower than the rates for those older than 5 years of age. 
The risk of myocarditis or pericarditis following mRNA vaccination is rare, relatively mild, and in most cases, resolves quickly with minimal, if any, medical treatment. On the other hand, in children and teens, the risk of getting COVID-19, and developing severe illness that could seriously impact the heart, are far greater than the risk of experiencing post-vaccine myocarditis. Learn more about myocarditis and weighing the risks in this article from the Children's Hospital of Philadelphia.
A severe allergic reaction (called anaphylaxis) can happen after any vaccine, including COVID-19 vaccines, but this is rare and happens in about one in a million people. Should this reaction occur, health care providers are prepared to treat it.
The known risks of COVID-19 illness (which include complications like myocarditis and pericarditis) outweigh the potential risk of having a serious side effect following vaccination. 


Have a positive vaccination experience 

Vaccines can cause some pain, stress, and anxiety for children all ages.  Fortunately, there are many strategies that can be used before and during the vaccination appointment that can help make the vaccination experience better. 

Jesse is going to get a COVID-19 vaccine and is a little nervous. Jesse brought a favourite toy and used belly breathing to feel calm. There was a tiny pinch on the arm, and it was over. That was easy! Jesse is now a COVID-19 vaccine superhero!

Print Jesse's story as a colouring page:

Read Jesse's story in colour!

Print and colour your own COVID-19 vaccine hero badge!



Date last reviewed: 
Thursday, Aug 11, 2022