The US Food and Drug Administration on Monday fully approved Pfizer's Covid-19 vaccine for people aged 16 and older, a move expected to trigger a new wave of vaccine mandates as the Delta variant batters the country.

"The FDA's approval of this vaccine is a milestone as we continue to battle the COVID-19 pandemic," acting FDA Commissioner Janet Woodcock said in a statement.

"While millions of people have already safely received COVID-19 vaccines, we recognize that for some, the FDA approval of a vaccine may now instill additional confidence to get vaccinated."