FDA to approve third injection of COVID for immunocompromised patients

U.S. drug regulators are set to approve a third dose of COVID-19 vaccines for people with weakened immune systems because a new study has shown the benefits of an additional injection in transplant patients.

A third dose of Moderna Inc.’s vaccine significantly increased antibody levels against the coronavirus in transplant patients, according to a comparison of an additional injection to a placebo in people with weakened immune systems. The Food and Drug Administration is expected to change the authorizations as of Thursday for vaccines from Moderna and Pfizer Inc. to allow additional doses for people with weakened immune systems, according to a person familiar with the matter who spoke under the guise of ‘anonymity.

Transplant patients and others with weakened immune systems often do not get adequate responses in their first round of vaccination and are at the top of the list for potential COVID-19 boosters. An advisory committee to the US Centers for Disease Control and Prevention should to discuss booster shots for immunocompromised people on Friday.

The FDA is closely monitoring data on supplemental dose studies in immunocompromised people, according to an email from the agency that said it would share more information in the near future.

The new study of 120 transplant patients looked at the effects of a third dose given two months after the second. One month after the third stroke, 55% of those who received it developed levels of antibodies that could provide significant protection.

Of the patients who received a placebo injection, rather than the third dose, only 18% showed the desired antibody levels, researchers at the University Health Network in Toronto found. Results from the Toronto Network’s Ajmera Transplant Center were published in the New England Journal of Medicine on Wednesday.

“I’m pretty excited with the results,” said Atul Humar, study author and chief of transplant medicine at Toronto General Hospital, one of several University of Toronto affiliated hospitals in the network. “It’s a slam dunk.”

The results were shared with Canadian regulars and the United States Food and Drug Administration, he said. Moderna played no role in the study.

Researchers in Toronto began the study after noticing that transplant patients who received two doses of the vaccine continued to get sick with COVID-19, according to Humar. They chose the Moderna vaccine for the three-dose study because it uses a greater amount of messenger RNA than a similar mRNA taken from Pfizer and BioNTech.

The number of protective T cells, another key immune fighter, was also higher in patients who received the true third dose rather than a placebo. The extra stroke was not associated with any case of organ rejection, and the side effects typical of COVID-19 strokes were only slightly more common after the third dose compared to placebo. The study was too small to assess whether the third stroke prevented people from getting sick with COVID-19.

“At this point, the benefit of the third dose of vaccination, at least with the mRNA-1273 vaccine, appears to outweigh the risks,” two New England Journal editors concluded in an editorial accompanying the study.

Bone marrow transplant patients and cancer patients on chemotherapy are also considered to have severely weakened immune systems, Humar said.

NBC News reported the news of the FDA’s plan to clear the shootings earlier on Wednesday.