The FDA expanded its emergency use authorizations for Moderna's and Pfizer's omicron-focused boosters Dec. 8 to include children as young as 6 months old.
Moderna's pediatric boosters are authorized for use in children between 6 months and 5 years, and Pfizer's option is authorized for children 6 months through 4 years of age.
The updated emergency use authorization differs between the two vaccine-makers. Children who received Moderna's original shot are now eligible to receive the omicron booster two months later. For Pfizer, only children who haven't received all three primary doses are eligible for the tweaked shot.
"Children in this age group who already completed their primary series would still be expected to have protection against the most serious outcomes from the currently circulating omicron variant," the FDA said, explaining the amendment to Pfizer's authorization. "The data to support giving an updated bivalent booster dose for these children are expected in January."
Similar to the modified adult boosters authorized in the fall, these bivalent boosters are targeted toward omicron subvariants BA.4 and BA.5. As of Dec. 3, BA.5 accounts for 13.8 percent and BA.4 makes up 0 percent of COVID-19 infections. Now, the nation's leading subvariants include BQ.1.1 (31.9 percent of cases) and BQ.1 (30.9 percent).
Early research shows the updated vaccines are less effective against newer variations of the coronavirus compared to their strength against BA.5, but a consensus has not been reached.
"Vaccines remain the best defense against the most devastating consequences of disease caused by the currently circulating omicron variant, such as hospitalization and death," Peter Marks, MD, PhD, director of the FDA's center for biologics evaluation and research, said in a statement. "Based on available data, the updated, bivalent vaccines are expected to provide increased protection against COVID-19."