On March 14, 2023 the FDA authorized the use of bivalent Pfizer-BioNTech vaccine as a booster dose for children 6 months through 4 years of age who had previously completed a 3-dose monovalent Pfizer-BioNTech primary series. Subsequently, on March 16, 2023, the CDC updated its Interim Clinical Considerations on the Use of COVID-19 Vaccines in the United States to reflect this change.

Previously, children 6 months through 4 years who had completed a 3-dose monovalent Pfizer-BioNTech primary series where not eligible for a bivalent Pfizer-BioNTech booster dose. The FDA authorization and CDC endorsement now allow those of all ages who are eligible for COVID-19 vaccines to receive a bivalent booster.

The booster should be administered at least 2 months after completion of the monovalent primary series.

Children 6 months to 4 years who had, in error, received a mixed Pfizer-BioNTech monovalent and Moderna monovalent series are also eligible for a bivalent Pfizer-BioNTech booster.