U.S. health authorities said Monday they have granted full approval for the Pfizer Inc. COVID-19 vaccine, making it the first such vaccine in the country where three have been administered under emergency use to prevent the spread of the novel coronavirus.

The full approval for the vaccine developed by Pfizer and its German partner BioNTech SE has been granted for people aged 16 or older, according to the Food and Drug Administration. Those aged 12 to 15 can get the shots under an emergency use authorization already in effect.

Supplied photo shows a tray of Pfizer Inc.'s COVID-19 vaccines. (Photo courtesy of Pfizer Inc.)(Kyodo)

The administration of President Joe Biden expects more Americans to receive COVID-19 vaccines now that one has received full approval from regulators, as a certain portion of the country has resisted inoculation despite a widespread campaign to promote the shots as a way to help end the pandemic.

The FDA announcement comes as the United States is seeing a sharp rise in COVID-19 infections, with the highly contagious Delta variant spreading across the country.

The government is keen to push up the vaccination rate as some people protest against mandatory mask-wearing in schools and elsewhere.

According to the latest data from the Centers for Disease Control and Prevention, 60.7 percent of the U.S. population has received at least one shot of a COVID-19 vaccine.

The Pfizer vaccine was approved for emergency use last December. The two other coronavirus vaccines available in the country are one developed by Moderna Inc. and another by Johnson & Johnson.

In a related move, New York Mayor Bill de Blasio announced Monday that all teachers and employees at public schools in the city will be required to have received at least one dose of a coronavirus vaccine by Sept. 27.

The policy is stricter than the previous requirement, under which it was possible to forgo the shots while presenting proof of testing negative for COVID-19 on a weekly basis.

New York City, once one of the hardest-hit areas by the coronavirus in the United States, has around 148,000 teachers and other workers in public schools subject to the latest measure.