May 10 (Reuters) - U.S. regulators on Monday authorized Pfizer and BioNTech's COVID-19 vaccine for use in children as young as 12, widening the country's inoculation program as vaccination rates have slowed significantly.

The vaccine has been available under an emergency use authorization to people as young as 16 in the United States. The vaccine makers said they had started the process for full approval for those ages last week.

The U.S. Food and Drug Administration said it was amending the EUA to include the millions of children aged 12 to 15.

(Reporting by Michael Erman; Editing by Caroline Humer, Bill Berkrot and Leslie Adler)