NBC News reports the decision comes 10 days after Pfizer-BioNTech requested authorization and two days after Moderna requested authorization.
“The FDA has determined that the currently available data support expanding the eligibility of a single booster dose of the Moderna and Pfizer-BioNTech Covid-19 vaccines to individuals 18 years of age and older,” Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said in a statement obtained by NBC News on Friday.
The FDA called on the Vaccines and Related Products Advisory Committee -- rather than seeking advice from its own independent advisory panel -- while reviewing trial data provided by both companies.
The CDC's advisory committee has also voted to recommend both the Pfizer-BioNTech and Moderna COVID-19 booster shots to adults of all ages, following the other advisory committee's decision hours earlier.
Pfizer said a Phase 3 clinical trial in which 10,000 participants were given the third dose of its vaccine showed safe and effective results.
The FDA's reported decision comes as the U.S. continues to see a rise in COVID-19 cases with the winter season approaching.
Several states, including Arkansas, California, Colorado and New Mexico, as well as New York City, have already allowed booster shots for all adults prior to the FDA's official signoff, which includes Moderna's vaccine.
Pfizer's booster shot is already authorized for U.S. adults age 65 and older, individuals living in long-term care facilities or people between the ages of 18 and 64 who work at high-risk COVID jobs or have underlying medical conditions.
The booster shot is given six months after an individual receives the two-dose vaccination series.