WASHINGTON, D.C. — A key advisory panel for the Food and Drug Administration (FDA) has endorsed the use of booster shots of Johnson & Johnson’s COVID-19 vaccine.

The agency’s Vaccines and Related Biological Products Advisory Committee voted unanimously Friday to recommend the boosters for the millions of Americans who have already received the initial dose, CNN and CNBC report.

The panel recommended the booster shots to everybody 18 and older who have already received J&J’s first shot. These boosters should be administered at least two months after the initial immunization, the panel recommended.

J&J announced last month that studies have shown that a booster shot of its vaccine increases protection against moderate cases of the coronavirus to 94% in the U.S.

Worldwide, J&J said booster shots made the vaccine 75% effective against moderate cases of the virus, and the company said booster shots were 100% effective in preventing severe cases of COVID-19.

The endorsement of the J&J boosters comes a day after the FDA panel endorsed the use of Moderna’s COVID-19 booster shots for seniors and other at-risk adults in the U.S.

Booster shots of the nation’s third COVID-19 vaccine made by Pfizer are already being administered after gaining full FDA approval last month.

Next up for Moderna and J&J, the FDA as a whole will consider the use of their booster shots. If the FDA issues a formal recommendation, the question will then be posed to the Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices, which has meetings scheduled to discuss the use of these boosters next Wednesday and Thursday. The director of the CDC would also need to issue final approval for the boosters.