Moderna is seeking authorization for children ages 6 through 17, while Pfizer's shot is for children aged 5 through 11.1

According to Reuters,2 "the U.S. Centers for Disease Control and Prevention … expects COVID-19 vaccine boosters targeting circulating variants of the virus to be available for children aged 5-11 years by mid-October."

Moderna's new bivalent COVID booster, mRNA-1273.222, sold under the brand name "Spikevax bivalent Original/Omicron," was authorized for adults over the age of 18 at the end of August 2022.3

In the U.S., the adult dose contains 25 micrograms of mRNA against the original Wuhan strain and 25 mcg of mRNA targeting Omicron variants BA.4 and BA.5.4 In the U.K., Moderna's bivalent booster (mRNA-1273.2145) contains mRNA against the original Wuhan strain and BA.1,6 an earlier Omicron strain that is no longer in circulation.7 8

Pfizer's bivalent booster also contain mRNA against the Wuhan strain, BA.4 and BA.5. The two bivalent boosters are only be available to those who have already received the primary two-dose series and/or a monovalent booster at least two months ago.9