FDA authorizes second dose of updated COVID-19 booster for older adults

April 18 (UPI) -- The Food and Drug Administration greenlighted a second dose of the updated COVID-19 booster for older adults and people with weakened immune systems on Tuesday.

For those who are 65 and older, they can receive a second dose of Pfizer and Moderna's booster shot, at least four months after their last dose, the agency said. It also amended rules for people who have not yet been vaccinated, saying that they can get a single dose of the updated vaccine.

Most individuals who have already received a single dose of the bivalent booster shot are not currently eligible for another one, the agency added.

Tuesday's decision simplifies the current vaccine schedule, with the original vaccines no longer authorized for use.

"At this stage of the pandemic, data support simplifying the use of the authorized mRNA bivalent COVID-19 vaccines and the agency believes that this approach will help encourage future vaccination," Peter Marks, the director of the FDA's Center for Biologics Evaluation and Research, said in a statement.

"Evidence is now available that most of the U.S. population 5 years of age and older has antibodies to SARS-CoV-2, the virus that causes COVID-19, either from vaccination or infection that can serve as a foundation for the protection provided by the bivalent vaccines."

The CDC said that 78% of new U.S. COVID-19 cases are caused by the Omicron subvariant XBB.1.5.

According to NBC News, a CDC report published in January found that the updated COVID-19 boosters reduced the risk of infection from the XBB.1.5 subvariant by nearly half.

Just 17% of the U.S. population has received a booster, according to the CDC.

"The available data continue to demonstrate that vaccines prevent the most serious outcomes of COVID-19, which are severe illness, hospitalization, and death," Marks said.