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My child is about to turn 12. Which COVID-19 vaccine should they get?

James D. Campbell, MD, MS, FAAP


The short answer: Your child should get the vaccine product that is recommended for their age. Here's why:

Age & vaccine dose

Right now, the only COVID-19 vaccine available for children in the U.S. is the Pfizer BioNTech mRNA vaccine. COVID-19 vaccination is recommended for children 5 years and older. The COVID shot for kids 5 years to 11 years of age is a lower dose than the dose recommended for people 12 years and older.

Can't the doctor just use a smaller amount of the vaccine for my younger child?

You may wonder why it's important to get the lower dose for younger kids. The reason is that the COVID-19 vaccine for children ages 5 to 11 years old was tested at the lower dose. This lower dose is what has been authorized and recommended.

Here are the doses of the Pfizer BioNTech mRNA vaccine, by age:

  • 12 through 17 years: 30-microgram COVID-19 vaccine—two separate doses, given 21 days apart.

  • 5 through 11 years: 10-microgram COVID-19 vaccine—two separate doses, given 21 days apart.

  • 5 through 12 years who have weakened immune systems from certain medical conditions or medications: 10-microgram COVID-19 vaccine three separate doses. Dose two is given 21 days after dose one. Dose three is given at least 28 days after dose two.

  • Under 5 years old: A COVID-19 vaccine is not yet available and the doses have not been determined.

Your child's doctor only can use the lower dose when they give the vaccine to 5- to 11-year-olds. There are many reasons for this. But the main reason is to make sure your child gets exactly the amount they need. The safest way for doctors to give your child the lower dose is to use the vials that are being specifically designed for younger children.

Why do we use age for the vaccine dose, but weight for measuring a dose of medicine?

Vaccines don't work the same way medicines such as antibiotics do. Antibiotics help your body get rid of germs when you are sick. And to get rid of germs, your body needs the right amount of medicine so it can make it to all parts of the body and find the problem. We dose antibiotics by weight so that the medicine can get to all the places of infection at levels needed by different size bodies.

A vaccine, on the other hand, helps your body know how to stop germs before they make you sick. Just a very small dose is all your cells need to learn how to stop germs.

Cells in your immune system go to the spot where the vaccine is given, rather than the vaccine needing to get all around the body. With information provided by the vaccine, the immune cells then launch a response to get rid of the virus.

Did you know?

The COVID vaccine dose that your child will get, if they are 5 to 11 years old, is very small—just 10 micrograms. The dose is about one-sixth the weight of a single grain of salt. That tiny amount is all it takes to prepare the immune system so it can stop germs from making someone sick.

Will the lower dose protect children enough?

The COVID vaccine clinical trial had more than 2,000 children. Researchers studied how well the vaccine worked in 5- to 11-year-olds. They also looked at data on how well the vaccine worked in 16- to 55-year-olds. The results? Children had the same immune response from the smaller dose and fewer minor side effects.

After a shot, your child might have mild symptoms as the immune system practices what it learned and how to avoid getting sick. The next time your child is in contact with that virus, the immune system will know how to stop your child from getting sick.

When can my younger child get the vaccine?

I am just as eager as you are to protect our youngest children from getting sick. Right now, children 6 months through 4 years old are being closely studied.

Soon, vaccine safety experts may talk about a COVID vaccine dose for these young children. For now, all the ways we protect children from getting sick from COVID are important. That includes getting the vaccine if you are old enough, especially if you interact with younger children. A booster dose is also strongly encouraged for adults and teens who got two doses of the mRNA COVID vaccine at least five months ago. Mothers can help protect babies when they get the vaccine before or during pregnancy and by breastfeeding.


Your child's doctor can answer questions about the vaccine. It's safe, and it works. It also is the best tool we have so we can stop the spread of the virus and protect your child from COVID-19.

More information

James D. Campbell, MD, MS, FAAP

James D. Campbell, MD, MS, FAAP, a pediatric infectious disease specialist based in Maryland, serves on the American Academy of Pediatrics Committee on Infectious Diseases.

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The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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