On Nov. 19, 2021, the U.S. Food and Drug Administration (FDA) announced that it had extended the emergency use authorization of a booster dose of the Moderna COVID-19 vaccine at the 50 ﾵg dose level to all adults aged 18 and older. This booster can be used in all individuals 18 years and older who have completed a primary vaccination with any other authorized or approved COVID-19 vaccine.

Prior to this authorizations, a single booster dose of the Moderna and Pfizer-BioNTech COVID-19 vaccines was authorized for administration to individuals 65 years of age and older, individuals 18 through 64 years of age at high risk of severe COVID-19 and individuals 18 through 64 years of age with frequent institutional or occupational exposure to SARS-CoV-2.