Moderate to severely immunocompromised people should get a third dose of mRNA COVID-19 Vaccine

The CDC announced on August 19, 2021, that moderate to severely immunocompromised people should receive an additional dose of mRNA COVID-19 vaccines (Pfizer/BioNTTech or Moderna vaccines), changing the series from 2 to 3. This recommendation does not apply to those who have received the Johnson & Johnson (Janssen) vaccine.

Individuals* that should get a third dose as soon as possible 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 2 years or are taking medicine to suppress 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 an immune response

*People who qualify for the third dose include anyone 12 years and older for the Pfizer/BioNTech vaccine and 18 years and older for the Moderna vaccine. The third dose should also be the same vaccine product used in the initial vaccine series and be at least 28 days after your second dose, no matter which product you had.

Emerging data are showing that moderate to severely immunocompromised people tend to have low, or no protection following two doses of an mRNA COVID-19 vaccine and may have an improved response after an additional dose.

How to get your third dose

There is no need to wait, find all the information you need about how to get your third dose.


What should immunocompromised people who received the J&J/Janssen vaccine do?

Currently, there is not enough data to determine whether immunocompromised people who received the Johnson & Johnson’s (Janssen) COVID-19 vaccine have experienced an improved antibody response following an additional dose. As soon as information is released, we will share it with you.

If I am moderate to severely immunocompromised, why should I get an additional dose?

Studies indicate some immunocompromised people don’t always build the same level of immunity after receiving the mRNA COVID-19 vaccination the way non-immunocompromised people do, therefore would benefit from an additional dose (third) to ensure adequate protection.

Talk to your health care provider about your medical condition and whether getting another dose is right for you.


This recommendation is NOT considered to be a booster dose and booster doses are NOT recommended at this time.