COVID-19 Vaccines for Moderately to Severely Immunocompromised People

Updated Aug. 16, 2021

NOTICE: CDC now recommends that people whose immune systems are compromised moderately to severely should receive an additional dose of mRNA COVID-19 vaccine after two initial doses. Widespread vaccination is a critical tool to help stop the pandemic. Read CDC’s statement.

What You Need to Know

• People who are moderate to severely immunocompromised are especially vulnerable to COVID-19 because they are more at risk of severe and prolonged illness.
• People who have compromised immune systems may benefit from an additional dose to make sure they have enough protection against COVID-19.
• CDC recommends that moderate to severely immunocompromised people receive an additional dose of mRNA COVID-19 vaccine after two initial doses.

CDC recommends that people with moderately to severely compromised immune systems receive an additional dose of mRNA COVID-19 vaccine at least 28 days after the second dose of Pfizer-BioNTech COVID-19 vaccine or Moderna COVID-19 vaccine.

CDC does not recommend additional doses or booster shots for any other population at this time.

Data on Decreased Immune Response Among Immunocompromised People

People who are moderate to severely immunocompromised make up about 3% of the adult population and are especially vulnerable to COVID-19 because they are more at risk of severe and prolonged illness.

Studies indicate some immunocompromised people don’t always build the same level of immunity after vaccination the way non-immunocompromised people do and may benefit from an additional dose to ensure adequate protection against COVID-19. In small studies pdf icon[2 MB, 36 Pages], fully vaccinated immunocompromised people have accounted for a large proportion of hospitalized “breakthrough cases.” That suggests immunocompromised people are more likely to transmit the virus to household contacts.

Who Needs an Additional COVID-19 Vaccine?

Currently, CDC is recommending that moderately to severely immunocompromised people receive an additional dose. It includes people who have:

• Been receiving active cancer treatment for tumors or cancers of the blood
• Received an organ transplant and are taking medicine to suppress the immune system
• Received a stem cell transplant within the last two years or are taking medication to stop the immune system
• Moderate or severe primary immunodeficiency (such as DiGeorge syndrome, Wiskott-Aldrich syndrome)
• Advanced or untreated HIV infection
• Active treatment with high-dose corticosteroids or other drugs that may suppress your immune response

People should talk to their healthcare provider about their medical condition and whether getting an additional dose is appropriate.