For people who received either Comirnaty (Pfizer) or Moderna’s COVID-19 vaccine series, a third dose of the same mRNA vaccine should be used. A person should not receive more than three mRNA vaccine doses. If the mRNA vaccine product given for the first two doses is not available or is unknown, either mRNA COVID-19 vaccine product may be administered. We do not expect vaccine providers to look up a patient’s prior doses prior to administration of the additional mRNA vaccine.