WASHINGTON — The US Food and Drug Administration (FDA) amended the emergency use authorization (EUA) for the Pfizer-BioNTech COVID-19 Vaccine to allow for use of a single booster dose, to be administered at least six months after the second dose in persons 65 years of age and older and individuals at high risk from the virus.

The FDA said in a statement late Wednesday that boosters are to be administered also to "individuals 18 through 64 years of age whose frequent institutional or occupational exposure to SARS-CoV-2 puts them at high risk of serious complications of COVID-19 including severe COVID-19."

"After considering the totality of the available scientific evidence and the deliberations of our advisory committee of independent, external experts, the FDA amended the EUA for the Pfizer-BioNTech COVID-19 Vaccine to allow for a booster dose in certain populations such as health care workers, teachers and day care staff, grocery workers and those in homeless shelters or prisons, among others," said Acting FDA Commissioner Janet Woodcock.

For his part, director of FDA's Center for Biologics Evaluation and Research Peter Marks said that the FDA "considered the (advisory) committee's input and conducted its own thorough review of the submitted data to reach today's decision."

"We will continue to analyze data submitted to the FDA pertaining to the use of booster doses of COVID-19 vaccines and we will make further decisions as appropriate based on the data," he added. The Centers for Disease Control and Prevention (CDC) and its advisers must give final approval for any booster doses.

The FDA’s decision on Wednesday largely follows recommendations given Friday by its key vaccine advisory committee at a more than eight-hour agency meeting. The CDC’s vaccine advisory committee is expected to vote Thursday afternoon on the FDA’s proposal. If it recommends approval and the CDC endorses it, booster shots could begin immediately.

Last week, the FDA’s Vaccines and Related Biological Products Advisory Committee voted 16-2 against distributing the vaccines to Americans 16 and older, before unanimously embracing an alternate plan to give boosters to older Americans and those at a high risk of suffering from severe illness if they get the virus.

Though Americans 65 and older make up roughly 17% of the US population, they are the most at risk of dying from COVID, accounting for more than 77% of all COVID deaths, according to the CDC.

The nonbinding decision by the FDA vaccine advisory committee was expected to be a controversial one as the Biden administration has said it wants to begin offering booster shots to the general public as early as this week, pending authorization from US health regulators.

While the agency hasn’t always followed the advice of its committee, it often does. Still, Marks reminded the panel on Friday that federal regulators did not have to accept its recommendation as written.

In clearing the shots, which only apply to people who received Pfizer’s original vaccine, the FDA cited a small study provided by the company of about 300 people who received the boosters, data provided by the UK as well as more comprehensive, but less rigorous data, from Israeli health authorities.

Some scientists, including at least two at the FDA, had said they weren’t entirely convinced every American who has received the Pfizer vaccine needed extra doses at this time.

However, the nation’s top health regulators, including CDC Director Dr. Rochelle Walensky, acting FDA Commissioner Dr. Woodcock and White House chief medical advisor Dr. Anthony Fauci, already endorsed Biden’s booster plan in August. — Agencies