The top US public health agency has said fully vaccinated people could forgo face coverings in almost all indoor and outdoor settings, a significant loosening of social distancing guidance that president Joe Biden hailed as a “great milestone” in the fight against the pandemic.

The latest update expands guidance from late April that allowed fully vaccinated people to go without face coverings in most outdoor settings. Before Thursday, the Centers for Disease Control and Prevention had recommended fully vaccinated people still wear masks in a crowded outdoor setting like a concert or sports event. That restriction has now been dropped.

Americans who received the final shot in a vaccine regimen at least two weeks earlier can now safely engage in almost all indoor activities without wearing a mask, the CDC said on Thursday.

“Anyone who is fully vaccinated can participate in indoor and outdoor activities, large or small, without wearing a mask or physical distancing,” Rochelle Walensky, CDC director, said at a press briefing.

“I think it’s a great milestone, a great day,” Biden said in a remarks shortly after the announcement.

“If you’ve been vaccinated, you don’t have to wear your mask, and you can shake hands and even give each other a hug,” he said. “But if you have not been vaccinated, please wear a mask.”

“We’ve gotten this far,” Biden added. “Please protect yourself until you get to the finish line.”

The CDC announcement will pave the way for a faster reopening of offices and schools, as states have dropped pandemic-related restrictions and allowed people to travel and socialise more freely. Some states, such as Texas, have already abandoned their own mask requirements.

Masks would still be required in certain indoor settings with specific health guidelines, such as hospitals or when travelling by air or public transport, Walensky said.

The decision to loosen mask restrictions for fully vaccinated people comes amid an encouraging drop in new coronavirus infections and hospitalisations across the country as more people are vaccinated, Walensky said. The US had averaged about 36,800 new infections a day over the past week, she said, a 23 per cent drop from a week earlier.

Andy Slavitt, a senior White House coronavirus adviser, said on Thursday that Covid-related deaths are hovering at about 590 a day, the lowest since April 2020, when the pandemic was in its early stages.

About 265m vaccine doses have been administered in the US since the rollout began in December, according to CDC data as of May 12. Almost 59 per cent of adult Americans have received at least one dose of a vaccine. Biden has set a goal of reaching 70 per cent by July 4.

Just over 35 per cent of the entire American population has been fully vaccinated. A CDC panel this week recommended the BioNTech/Pfizer jab for use by 12 to 15-year-olds, paving the way for millions of adolescents to become eligible for a shot.

Anthony Fauci, one of Biden’s top coronavirus advisers, sought to allay some of the confusion about mask use outdoors for fully vaccinated people earlier on Thursday.

“If you are going into a completely crowded situation where people are essentially falling all over each other, then you wear a mask. But any other time if you are vaccinated and you’re outside, put aside your mask, you don’t have to wear it,” he said during an interview with CBS This Morning.

Biden and Kamala Harris, vice-president, were in a meeting at the White House with Republican senators when the CDC announcement was made.

The senators and the president removed their masks upon hearing the news, Shelley Moore Capito, the Republican senator from West Virginia and de facto chief negotiator for her colleagues, told reporters after the meeting.

First Lady Jill Biden was also photographed mask-less during a trip to West Virginia, where she was travelling with Democratic senator Joe Manchin, his wife, Gayle Manchin, and Hollywood actress Jennifer Garner. The Bidens have rarely been seen without masks since the onset of the pandemic last year.

When asked by a reporter what the reduced restrictions meant for the people of West Virginia, Manchin replied: “It means get vaccinated. We feel free!”

“We feel naked,” Jill Biden said, then adding: “I didn’t mean it that way!”

Additional reporting by Kiran Stacey