Yes. The CDC recommends that people with moderately to severely compromised immune systems receive an additional (third) dose of mRNA COVID-19 vaccine at least 28 days after a second dose of Pfizer-BioNTech COVID-19 vaccine or Moderna COVID-19 vaccine. Studies have found that 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 of an mRNA vaccine to ensure adequate protection against COVID-19.
Smaller studies found fully vaccinated, immunocompromised people made up a large proportion of hospitalized “breakthrough cases.” Currently, the CDC is recommending that moderately to severely immunocompromised people receive an additional (third) dose. This additional dose is intended to improve immunocompromised people’s response to their initial vaccine series.
This 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 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 your immune response
This third dose of a Pfizer or Moderna vaccine is the same dose that is administered in the primary vaccine series. This is different from the booster dose (specifically for the Moderna vaccine), which is a half dose (50 micrograms) when given as a booster, but a full dose (100 micrograms) when given to someone who is immunocompromised as a third dose, as outlined above. However, the Pfizer third dose and Pfizer booster dose is the same dose.