U.S. regulators on Friday authorized the emergency use of coronavirus vaccines developed by Pfizer Inc. and Moderna Inc. to include children as young as 6 months old.

"We are the first country to protect our youngest children with COVID-19 vaccines," President Joe Biden said in a statement, emphasizing the effectiveness and safety of the inoculations.

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

In the United States, the Pfizer vaccine had so far been authorized for use in individuals 5 years of age and older, while the Moderna vaccine had been approved for use in adults at least 18 years old.

The latest authorization by the Food and Drug Administration paves the way for COVID-19 vaccinations for children under age 5.

"As we have seen with older age groups, we expect that the vaccines for younger children will provide protection from the most severe outcomes of COVID-19, such as hospitalization and death," FDA Commissioner Robert Califf said in a press release.

The Pfizer vaccine will be administered as a primary series of three doses in individuals aged 6 months through 4 years. The Moderna type will involve two doses to individuals 6 months through 17 years of age.

As early as next week, pending recommendations from the Centers for Disease Control and Prevention, parents will be able to start scheduling vaccinations for the youngest children.

Nearly 67 percent of the total U.S. population has so far been fully vaccinated, according to data from the CDC.