Update 8/13/2021: third doses are now authorized in the updated EUA for people who are moderately or severely immunocompromised. Updated CDC guidance This includes:

1. Active treatment for solid tumor and hematologic malignancies
2. Receipt of solid-organ transplant and taking immunosuppressive therapy
3. Receipt of CAR-T-cell or hematopoietic stem cell transplant (within 2 years of transplantation or taking immunosuppression therapy)
4. Moderate or severe primary immunodeficiency (e.g., DiGeorge, Wiskott-Aldrich syndromes)
5. Advanced or untreated HIV infection
6. Active treatment with high-dose corticosteroids (i.e., ≥20mg prednisone or equivalent per day), 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

Additional notes:

1. Third dose must be of the same type of vaccine as the first two doses. 
2. Third dose must be more than 28 days after second dose.
    
    
3. Pfizer is available for people 12 years and older, and Moderna for people 18 years and older. 
4. Proof: self-attestation of having one of the conditions listed above, no prescription or doctor's note required.
5. If you've received Johnson & Johnson/Janssen vaccine: Currently there are not data to support the use of an additional mRNA COVID-19 vaccine dose after a primary Janssen COVID-19 vaccine in immunocompromised people.  

Immunocompromised individuals may still have a reduced immune response and need to take steps to reduce their risk of exposure, such as:

1. Wearing a mask
2. Staying 6 feet apart from others they don't live with
3. Avoiding crowds and poorly ventilated indoor spaces until advised by their healthcare provider.