• The FDA could still withhold the announcement
  • The emergency use approval may only apply to immunocompromised patients
  • The CDC estimates that at least 2.7% of all adults in the U.S. are immunocompromised

The U.S. Food and Drug Administration may authorize a third shot of COVID-19 vaccine for the immunocompromised within this week, a report said, citing a source with knowledge of the discussions.

The move could give some vulnerable Americans access to a booster shot of the current two-dose Pfizer and Moderna vaccines. However, the FDA could still withhold an announcement of the third shot, the source said, CNN reported.

"The FDA is closely monitoring data as it becomes available from studies administering an additional dose of the authorized COVID-19 vaccines to immunocompromised individuals," an FDA spokesperson was quoted as saying by the report. "The agency, along with the CDC, is evaluating potential options on this issue, and will share information in the near future," the official added.

A group of vaccine advisers for the Centers for Disease Control and Prevention are scheduled to meet Friday to discuss the third dose of COVID-19 vaccines for people with compromised immune systems.

Based on an estimate by the CDC, 2.7% of all adults in the U.S., or about 9 million Americans, are immunocompromised. The agency defines immunocompromised as patients who are organ transplant recipients, people undergoing cancer treatments, people with HIV, and people with solid tumor malignancies, among others. 

In a small study published in June by researchers at Johns Hopkins University, at least 24 of 30 organ transplants recipients who received two doses of the Moderna or Pfizer vaccine did not develop antibodies against COVID-19. While the six other patients developed antibodies following the vaccination, the low levels still left them vulnerable to the virus. 

After the researchers gave the patients a third dose of the COVID-19 vaccine, eight of the 24 patients who previously had no antibodies had an increase. The six patients who had low levels of antibodies following the second shot also had an increase after the booster dose. 

“To me the main message here for transplant patients and immunosuppressed patients is a message of hope,” Dr. Dorry Segev, an author of the study and associate vice chair for research and professor of surgery at Johns Hopkins University, was quoted as saying by NBC News.

If the FDA grants emergency use authorization for the booster shot, it may not be applied to fully vaccinated, otherwise healthy individuals. 

Last week, the Mississippi Department of Health advised its state’s medical providers to administer the third dose of vaccine to immunocompromised patients, as reported by The Hill

Steven R. Brandenburg, 46, removed Moderna vaccine vials from their refrigerator unit on purpose, according to court documents Steven R. Brandenburg, 46, removed Moderna vaccine vials from their refrigerator unit on purpose, according to court documents Photo: AFP / Apu GOMES