Centers for Disease Control Director Dr. Rochelle Walensky signed off on the Food and Drug Administration's authorization of the bivalent COVID-19 booster shot for children as young as five years old.

The bivalent vaccine targets the omicron variant, which continues to be the dominant strain across the U.S.

The authorizations are different for the Pfizer and Moderna vaccines.

The Pfizer booster can be administered at least two months following completion of the primary vaccine series in children five years and older.

Moderna's booster is authorized for children six years and older.

"Updated COVID-19 vaccines add Omicron BA.4 and BA.5 spike protein components to the current vaccine composition, helping to restore protection that has waned since previous vaccination and targeting recent Omicron variants that are more transmissible and immune-evading," the CDC said in a statement.

Just over 30% of children as young as five have completed their primary vaccine series, the CDC reports.

Wednesday's authorization comes about three months after the FDA authorized the bivalent booster for people for adults.