President Joe Biden hailed the "stunning" progress that the United States has made in the fight against the coronavirus pandemic, as he addressed the nation from the White House on Tuesday.

"While we still have a long way to go in this fight, a lot of work to do in May and June to get us to July 4, we've made stunning progress because of all of you, the American people," Biden said, referencing Independence Day as a milestone goal in the fight against the virus.

"Cases and deaths are down -- down dramatically from where they were when I took office."

Biden spoke out as the country's premier health agency, the Centers for Disease Control and Prevention, issued new guidance notifying Americans vaccinated against the coronavirus that they no longer need to wear masks outdoors.

Fully vaccinated people can eat, walk or attend small gatherings outside without a mask --as long as they are not at crowded events.

"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.

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.

The government announced on Monday it would be sending up to 60 million doses of the AstraZeneca vaccine abroad, after critics had accused Washington of "hoarding" the British-developed vaccine, which is not authorized in the country and will likely not be required to vaccinate Americans.