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Second bivalent dose allowed for those at high risk from COVID-19

April 20, 2023

The U.S. Food and Drug Administration (FDA) and the U.S. Centers for Disease Control and Prevention (CDC) have taken steps to simplify COVID-19 vaccine recommendations and to provide additional protection to high-risk populations. 

On April 18, 2023, FDA authorized the bivalent version of both Pfizer/BioNTech’s and Moderna’s COVID-19 mRNA vaccines for use as all vaccine doses, primary or booster, in those who are at least 6 months old. Simultaneously, FDA revoked the emergency use authorizations (EUAs) for both monovalent versions of the vaccines. The bivalent vaccines protect against both the original 2019 strain of COVID-19 and the newer omicron BA.4/BA.5 variant. Previously, the bivalent vaccines were only authorized to be used as boosters following a primary vaccination series with a monovalent vaccine.

In addition, FDA authorized a second booster dose of either bivalent vaccine for those who are 65 and older or who are moderately to severely immunocompromised and have already received one bivalent booster dose. Those who are 65 and older must wait four months between bivalent doses, and those who are immunocompromised must wait two months between bivalent doses. The exception is children younger than 5 years old who are immunocompromised—their eligibility for a second bivalent booster depends on their vaccine history.

On April 19, 2023, CDC released updated COVID-19 vaccine recommendations in line with FDA’s authorization changes. CDC recommends that everyone 6 and up receive at least one dose of a bivalent mRNA vaccine, regardless of previous vaccination status. For those 65 and older or who are immunocompromised, CDC allows an additional dose of bivalent mRNA vaccine. Again, children younger than 5 who are immunocompromised have different recommendations depending on past vaccinations.


This page contains general medical and/or legal information that cannot be applied safely to any individual case. Medical and/or legal knowledge and practice can change rapidly. Therefore, this page should not be used as a substitute for professional medical and/or legal advice.