COVID-19 vaccine third dose: Who is eligible and how to get one

Time & Date

Monday, August 16, 2021

On Aug. 13, 2021, the CDC made recommendations for a third dose of the mRNA COVID-19 vaccine following the initial 2 doses for those whose immune systems are moderately to severely compromised. 

People in this group are especially vulnerable to COVID-19 because they are at greater risk of serious and prolonged illness. They make up about 3% of the adult population.  Emerging data show that immunocompromised individuals who have low or no protection following 2 doses of mRNA COVID-19 vaccines may have an improved antibody response after an additional dose of the same vaccine.

There is scientific consensus that widespread vaccination is the most effective tool to stopping the pandemic. 

Who is eligible to receive a third COVID-19 vaccine?

Currently, CDC is recommending the third dose for only moderately to severely immunocompromised persons. This includes those individuals 12 and older 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 (i.e., ≥20mg prednisone or equivalent per day) or other drugs that may suppress your immune response, such as alkylating agents, antimetabolites, transplant-related immunosuppressive drugs, cancer chemotherapeutic agents classified as severely immunosuppressive, TNF blockers, and other biologic agents that are immunosuppressive or immunomodulatory. The UT Health Science Center San Antonio Vaccine Task Force recommends methotrexate also be included in this list, but not hydroxychloroquine. 

• CDC does not recommend additional doses or booster shots for any other population at this time.
• The U.S. Department of Health and Human Services has announced a plan to begin offering COVID-19 mRNA vaccine booster shots this fall, possibly as early as mid-September. 

  UT Health San Antonio's plans for providing these booster shots will be communicated as they are finalized.

Which brand of the COVID-19 vaccine should I get?

At this time, CDC recommendation for a third dose of vaccine applies only to those with comprised immune systems who received an mRNA vaccine (Pfizer or Moderna). Preferably, your third dose should be the same vaccine brand you received for your first series of COVID-19 vaccines (Pfizer or Moderna). However, if that brand is not available, you can receive either mRNA vaccine as the third dose.

This recommendation does not apply to those who received the Johnson & Johnson (J&J) vaccine. It is expected that the need for additional doses in these persons will be addressed later after more data is available.

How long should I wait to receive my third COVID-19 vaccine?

CDC recommends the additional dose of an mRNA COVID-19 vaccine (Pfizer or Moderna) be administered at least four weeks (28 days) after the second dose.

Where can I learn more about getting a third COVID-19 vaccine?

Visit the CDC.gov website to learn the most up-to-date information about third-dose mRNA vaccines and how to receive one.