Facts About Third Doses of Vaccines (Boosters) for the Immunocompromised

People with immune systems that are moderately to severely compromised, including many cancer patients, make up about 3 percent of the adult population and are especially vulnerable severe illness from COVID-19, according to the U.S. Centers for Disease Control and Prevention (CDC).

On Aug. 12, the U.S. Food and Drug Administration (FDA) amended the emergency use authorizations (EUAs) for both the Pfizer-BioNTech and Moderna COVID-19 vaccines to allow for the use of an additional dose in certain immunocompromised individuals. Both vaccines initially require two shots to be fully vaccinated. The FDA specifically mentioned solid organ transplant recipients or those “who are diagnosed with conditions that are considered to have an equivalent level of immunocompromise.”

The CDC also approved these additional doses. Individuals who are immunocompromised in a manner similar to those who have undergone solid organ transplantation have a reduced ability to fight infections and other diseases, and they are especially vulnerable to infections, including COVID-19.

Michael J. Zinner, M.D., CEO and executive medical director of Miami Cancer Institute.

Those especially vulnerable include patients under cancer treatments for tumors or cancers of the blood, both the FDA and CDC specify. Current cancer patients or cancer survivors who may still be taking medications that may suppress their immune response should check with their doctor if they are unsure or have any questions about third doses.

“Our patients may certainly qualify for third-dose vaccines and they should check with their oncologists if they have any questions or concerns,” explains Michael J. Zinner, M.D., CEO and executive medical director of Miami Cancer Institute, part of Baptist Health. “Post-treatment cancer survivors may also qualify and should seek guidance on third doses.”

The CDC recommends that people with moderately to severely compromised immune systems receive an additional dose of the mRNA vaccines from Pfizer and Moderna at least 28 days after a second dose.

Who Needs a Third Dose (Booster) of a COVID-19 Vaccine?

Currently, the CDC recommends that moderately to severely immunocompromised people receive an additional vaccine dose. They include 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.

Louise Morrell, M.D., medical director of Lynn Cancer Institute at Boca Raton Regional Hospital.

Both the FDA and the CDC are expected to approve third doses, or boosters, for everyone who is fully vaccinated in coming weeks. Both agencies emphasize that the current third doses for the immunocompromised are not for those who have many underlying health issues that put them in the high-risk category for severe illness from COVID-19 — unless they fall into the outlined categories for a third dose.

“For now, an additional shot is only recommended for people who meet the CDC’s criteria for being immunocompromised,” said Louise Morrell, M.D., medical director of Lynn Cancer Institute at Boca Raton Regional Hospital, part of Baptist Health. “Many of those are cancer patients. They are especially vulnerable to getting sick and requiring hospitalization from COVID.”

The CDC states that clinical studies have found fully vaccinated, immunocompromised people to have accounted for a disproportionate number of hospitalized “breakthrough cases.”

Currently, Miami Cancer Institute and Lynn Cancer Institute are not providing the third COVID-19 vaccine shot recommended for immunocompromised patients. Those who qualify for this third dose should obtain it at local pharmacies.