This post was last updated May 17, 2022.

You ask, we answer. In each edition of “Ask a Pediatrician,” Connecticut Children’s pediatric experts respond to a question from our community.

The CDC and FDA authorized the Pfizer COVID-19 vaccine primary series and booster for anyone over the age of 5, and for the Moderna and Johnson & Johnson vaccines for anyone over the age of 18. They’ve also said it’s safe and effective to mix and match different vaccines.

So we're hearing a lot of questions about young people and COVID-19 boosters.

Connecticut Children’s Physician-in-Chief Juan C. Salazar, MD, MPH, FAAP, shares answers.

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Is my child eligible for a COVID-19 booster shot?

Dr. Salazar: Right now, your child can only get a COVID-19 booster if they’re at least 5 years old. It also depends on when they got their shot.

If your child originally got Pfizer’s vaccine:

  • Age 5 and older
  • Received their last shot at least five months ago

If your child originally got Johnson & Johnson’s vaccine:

  • Age 18 or older
  • Received their shot at least two months ago

If your child originally got Moderna’s vaccine:

  • Age 18 or older
  • Received their last shot at least six months ago

> Related: The COVID-19 Vaccine and Younger Kids: FAQs for Ages 5 to 11

If my child is eligible, should they get a COVID-19 booster shot?

Yes. Hospitalizations in kids are surging right now due to the highly contagious Omicron variant. The vaccines are your child’s best protection against severe illness and hospitalization – and boosters seem to increase that protection significantly. That’s why the CDC is now urging everyone 5 and older to get a booster shot once they’re eligible.

If you or your child have questions, talk with your child’s doctor. They know their health history, and can give personalized advice.

Young boy getting his COVID-19 vaccine

Are booster shots any different from the original vaccines?

The Pfizer and Johnson & Johnson boosters are the same as their original shots. The Moderna booster is half of the original dosage: The booster shot is just 50 micrograms, compared to 100 micrograms each for the first and second shots.

Can my child get a booster of a different COVID-19 vaccine than their original doses?

If they’re at least 18 years old, yes. The CDC has authorized this “mix and match” approach for adults.

If your child is age 5 to 17, they can only get the Pfizer booster.

If my child is old enough to mix and match, how should they decide whether to stick with the same COVID-19 vaccine they originally got, or switch to a different shot?

As a reminder, this decision only applies if your child is age 18 or older.

In most situations, the CDC recommends either the Pfizer or Moderna booster (not Johnson & Johnson). Between these two, the decision comes down to personal preference. Your child should talk with their doctor for help deciding. They may like the familiarity of knowing how their body responded to the original COVID-19 vaccine, and want to stay with that. Or maybe they’d like to try a different vaccine, because it’s more convenient. Their doctor can weigh in with any concerns or recommendations

> Related: Can Kids Get the COVID-19 Vaccine and Flu Shot at the Same Time?

If my child is immunocompromised, can they have a third dose of the Pfizer COVID-19 vaccine?

Separate from the booster eligibility above, immunocompromised children ages 5 and up are now eligible for a third primary series dose (different from a booster) of Pfizer’s COVID-19 vaccine. But this is only if your child has a condition or treatment that seriously weakens their immune system, like certain cancer treatments or having had an organ transplant. If you think this applies to your child, talk with their doctor.

In the future, will my family need regular COVID-19 boosters, like the annual flu shot?

It’s possible. It depends on a lot of factors – like how the COVID-19 virus continues to evolve, how the world continues to respond, and how well the vaccines continue to work. We may eventually see different booster shots for different strains of COVID-19, or a booster shot that works against multiple strains, similar to how the flu vaccine is created each year.

Right now, adults 50 and older are eligible for a second booster shot.

What other topics would you like us to address in our “Ask a Pediatrician” series? Let us know at askapediatrician [at] connecticutchildrens.org (askapediatrician[at]connecticutchildrens[dot]org).

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