Persons with Moderate to Severe Immune Compromise

  • Consider an additional dose of an mRNA COVID-19 vaccine at least 28 days after an initial 2-dose primary mRNA COVID-19 vaccine series for people with moderate to severe immune compromise due to a medical condition or receipt of immunosuppressive medications or treatments.
  • Administer the same vaccine product for the initial 2-dose primary series and the additional dose. If the vaccine product cannot be determined or is no longer available, administer either mRNA COVID-19 product.
  • These individuals do not need a booster dose of vaccine. They should receive a maximum of 3 doses of an mRNA COVID-19 vaccine (i.e., a 2-dose primary series and one additional dose).
  • Counsel immunocompromised people about the potential for a reduced immune response to COVID-19 vaccines and the need to continue to follow current prevention measures to protect themselves against COVID-19 until advised otherwise by their healthcare professional.
  • For more information, please see Interim Clinical Considerations for Use of COVID-19 Vaccines Currently Authorized in the United States at


Page last reviewed: October 8, 2021