COVID-19 vaccines for infants, toddlers

The use of COVID-19 vaccines in infants and toddlers in the U.S. has cleared the final hurdles.

Food and Drug Administration (FDA) advisers voted unanimously to recommend emergency use authorization for Moderna and Pfizer's COVID-19 vaccines for young children. The Centers for Disease Control and Prevention followed by authorizing health care professionals to begin vaccinating the youngest of children.

Moderna's vaccine is for children ages 6 months to 5 years, and Pfizer's vaccine is for children ages 6 months to 4 years. Both vaccines are made using messenger RNA.

Moderna's vaccine is administered in two doses, and it contains one-quarter the amount of antigen as its adult dose. Pfizer's vaccine contains one-tenth of the amount of antigen as its adult dose, and it is given as three doses.

"It's a good step forward because now we can provide COVID-19 vaccination to almost everybody in the U.S. if we need to," says Richard Kennedy, Ph.D., co-chair of Mayo Clinic's Vaccine Research Group.

"Now we have got new variants, so we'll start to see variant-specific vaccines. But now we have safety data on these vaccine types and new formulations," says Dr. Kennedy. " "And, so, when they come out with an omicron vaccine, or (a vaccine for) whatever the next variant is, they've got all this safety data so they don't have to go retrace all their steps. They can start using it immediately."

The long-awaited authorization came after weighing the safety and effectiveness of the vaccines.

"The FDA and other regulatory agencies do a very deep dive into the safety data, and that's why you typically see a rollout of a vaccine in several stages. Healthy adults can get it, and then they drop the age range a little bit. And they check it and make sure it's safe. And they drop it again. There's this stepwise series of let's expand the people we know we can safely vaccinate, and that's what we're seeing here — the result of that testing," says Dr. Kennedy.

As far as young kids eventually needing booster vaccinations, Dr. Kennedy says that's yet to be determined.

"We'll have to wait and see what they decide with that. The clinical trials are still ongoing. For children who are vaccinated, they're going to continue to watch and see whether or not the immune system wanes as quickly as it does in adults," says Dr. Kennedy. "We've seen that with adults that you get your booster and you're protected for a few weeks to a few months, and then the level of antibody you have gradually declines. And, so, we will see more and more recommendations for boosters, and those boosters will be for all different age groups. And we'll probably see some age-specific recommendations, as well."

Dr. Kennedy discusses COVID-19 vaccines for young children in this video:

Information in this post was accurate at the time of its posting. Due to the fluid nature of the COVID-19 pandemic, scientific understanding, along with guidelines and recommendations, may have changed since the original publication date.