Americans vaccinated against the coronavirus no longer need to wear masks outdoors, except at crowded events, US government health authorities said on Tuesday.

Under the newly released guidance from the Centers for Disease Control, fully vaccinated people can eat, walk or attend small gatherings outside without a mask.

"If you are fully vaccinated, you can start doing many things that you had stopped doing because of the pandemic," the government body said in a statement.

Masks are still considered necessary for vaccinated people if they are at concerts, parades or large sporting events, even when outdoors, the CDC said.

Indoor activities remain under a masks recommendation. This includes movie theaters and even "uncrowded" indoor shopping centers and museums, the CDC said.

The CDC stressed that its newly relaxed guidance only applies to people who have had their full vaccine doses and are two weeks past the final shot.

More than half of all US adults have now received at least one of two vaccine doses. The surging rate of people seeking out vaccines has begun to taper, but new COVID-19 cases are also falling.