On April 18, 2023, the U. S. Food and Drug Administration (FDA) amended the emergency use authorizations (EUAs) of Moderna and Pfizer-BioNTech COVID-19 bivalent mRNA vaccines. This action included authorizing the current bivalent vaccines to be used for all doses administered to individuals six-months of age and older, including additional doses for certain populations.  On April 19, 2023, CDC’s Advisory Committee on Immunization Practices (ACIP) met and reviewed COVID-19 vaccine safety and efficacy data. The CDC updated its Interim Clinical Considerations for the Use of COVID-19 Vaccines Currently Authorized in the United States on April 22, 2023, which includes the following guidance:

• All individuals six months of age and older who previously completed a primary monovalent COVID-19 vaccine series but have not received bivalent vaccine should receive at least one dose of a bivalent vaccine.
• Individuals 6 years through 64 years of age, who are not moderately to severely immunocompromised, and who have NOT completed a primary COVID-19 vaccine series, including those who are completed unvaccinated against COVID-19, should receive a single dose of a bivalent vaccine to meet current COVID-19 vaccine recommendations.
• Most individuals who have already received a single dose of the bivalent vaccine are not currently eligible for another dose.
• The monovalent Moderna and Pfizer-BioNTech COVID-19 vaccines are no longer authorized for use in the United States.

Populations with indications for more than one bivalent COVID-19 dose:

• Children 6 months through 5 years of age are eligible for bivalent COVID-19 mRNA vaccines. The dose and number of doses depends on whether their prior vaccination status (unvaccinated or have completed 1 or more doses of monovalent COVID-19 mRNA vaccine. These children should complete their series using the same brand (Moderna or Pfizer-BioNTech). See CDC Interim Clinical Considerations for the Use of COVID-19 Vaccines Currently Authorized in the United States for the specific scenarios.
• Individuals 65 years of age and older who have received a single dose of a bivalent vaccine may receive one additional dose at least four months following their initial bivalent dose.
• Most individuals with certain kinds of immunocompromising conditions who have received a bivalent COVID-19 vaccine may receive a single additional dose of a bivalent COVID-19 vaccine at least 2 months following a dose of a bivalent COVID-19 vaccine. Additional doses may be administered at the discretion of, and at intervals determined by, their healthcare provider.