You have likely heard that the Pfizer COVID vaccine has been authorized for our younger kids, between ages 5 to 11 years.

While that’s great news for those of us who want to vaccinate and protect our kids, the announcement of these vaccines has caused some confusion, even before they were authorized.
Why?
“COVID-19 vaccines awaiting authorization for children ages 5-11 years will have different doses, dilution requirements and storage conditions than the vaccines currently available for adolescents and adults, according to Pfizer.”
Pfizer’s COVID-19 vaccine for kids would require different doses, dilution, storage
These COVID vaccines for kids will be a little different than those given to teens and adults.
What’s Different About COVID Vaccines for Kids?
Before we get into those differences, folks should understand that it is not that uncommon for there to be different formulations of vaccines for adults and kids.
That’s what we have for:
- DTaP (infants and young children) vs Tdap (teens and adults)
- hepatitis A vaccine – children get half the adult dose
- hepatitis B vaccine – children get half the adult dose
- standard influenza vaccines (all ages) vs high dose flu shot (seniors)
So the idea that COVID vaccines for children, teens, and adults have some differences shouldn’t be at all surprising!
“The COVID-19 vaccine manufactured by Pfizer and BioNTech is proposed to be given in two 10-microgram (mcg) doses administered 21 days apart. The dosage is one-third of the adolescent and adult dose.”
Pfizer’s COVID-19 vaccine for kids would require different doses, dilution, storage
But why do younger children get a small dose of this COVID vaccine?

The smaller dose was chosen because in clinical trials it was found to be safe and provided the same immune response as larger doses!
“Pfizer Inc. (NYSE: PFE) and BioNTech SE (Nasdaq: BNTX) today announced results from a Phase 2/3 trial showing a favorable safety profile and robust neutralizing antibody responses in children 5 to 11 years of age using a two-dose regimen of 10 µg administered 21 days apart, a smaller dose than the 30 µg dose used for people 12 and older. The antibody responses in the participants given 10 µg doses were comparable to those recorded in a previous Pfizer-BioNTech study in people 16 to 25 years of age immunized with 30 µg doses. The 10 µg dose was carefully selected as the preferred dose for safety, tolerability and immunogenicity in children 5 to 11 years of age.”
Pfizer and BioNTech Announce Positive Topline Results From Pivotal Trial of COVID-19 Vaccine in Children 5 to 11 Years
And since you get the same immune response, that should put to rest any ideas of parents wanting to wait until their kids actually turn 12 to get them vaccinated.
“COVID-19 vaccines are life-saving vaccines. Individuals should receive the first vaccine they are eligible to receive and that is available in their community. Delaying immunization leaves an individual vulnerable to infection for a longer period of time, placing them at greater risk of serious illness and death.”
About the COVID-19 Vaccine: Frequently Asked Questions
Get your child vaccinated and protected with an age appropriate dose when a COVID vaccine becomes available to your child. Any delay simply puts them at risk to get COVID.
Are there any other differences?

To help them last longer at refrigerator temperatures (10 weeks vs 4 weeks), Pfizer COVID vaccines for younger kids do have a different buffer. They switched from using salts to tromethamine, which is also used in the Moderna COVID vaccine.

In addition to a smaller dose, younger kids get a smaller volume of vaccine in their injection.
And not surprisingly, which form of the vaccine they receive depends on their age on the day that they are vaccinated.

So if a child turns 12 years of age in between their first and second dose, they might receive the 10 μg (orange cap) Pfizer COVID vaccine for their first dose and the 30 μg (purple cap) vaccine for their second dose.
More on COVID Vaccines for Kids
- Are Kids Dying With COVID-19?
- Off-Label Use of COVID Vaccines for Kids
- Why You Should Get Vaccinated Even Though You Had COVID
- COVID Vaccine Booster Doses
- Do COVID Vaccines Prevent Transmission of the SARS-CoV-2 Virus?
- The Truth About COVID-19 Vaccines
- I’m Not Anti-Vaccine, I Just Don’t Believe in the COVID-19 Vaccine
- Is It Too Late to Get a COVID Vaccine?
- Myths About Your Baby’s Immature Immune System
- FDA – Fact Sheet for Healthcare Providers Administering Vaccine (Vaccination Providers) Emergency Use Authorization (EUA) of the Pfizer-Biontech Covid-19 Vaccine to Prevent Coronavirus Disease 2019 (Covid-19) for 5 Through 11 Years of Age
- FDA – Vaccine Information Fact Sheet for Recipients and Caregivers About the Pfizer-Biontech Covid-19 Vaccine to Prevent Coronavirus Disease 2019 (Covid-19) for Use in Individuals 5 Through 11 Years of Age
- CDC – Interim Clinical Considerations for COVID-19 Vaccine in Children Ages 5–11 Years
- CDC – Prevaccination Checklist for COVID-19 Vaccines
- CDC – V-safe After Vaccination Health Checker
- ACIP Presentation Slides: November 2-3, 2021 Meeting
- COCA – Pediatric COVID-19 Vaccines: CDC’s Recommendations for Pfizer BioNTech COVID-19 Vaccine Primary Series in Children 5–11 Years Old
- COCA – What Clinicians Need to Know about the Recent Updates to CDC’s Recommendations for COVID-19 Boosters
- FDA – Vaccines and Related Biological Products Advisory Committee October 26, 2021 Meeting Announcement
- CDC – ACIP Presentation Slides: November 2-3, 2021 Meeting
- Expiration Extension: Pfizer-Biontech Covid-19 Vaccine