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.