US health officials have eased mask-wearing guidance for people who are fully vaccinated, allowing them to stop using face coverings outdoors in crowds and in most indoor settings.
"Today is a great day for America," President Joe Biden said during a Rose Garden address on Thursday heralding the new guidance from the Centres for Disease Control and Prevention (CDC).
"If you are fully vaccinated, you no longer need to wear a mask," he said, summarising the new guidance and encouraging more Americans to roll up their sleeves. "Get vaccinated - or wear a mask until you do."
The guidance still calls for wearing masks in crowded indoor settings such as buses, planes, hospitals, prisons and homeless shelters, but it will help clear the way for reopening workplaces, schools, and other venues - even removing the need for social distancing for those who are fully vaccinated.
"We have all longed for this moment - when we can get back to some sense of normalcy," said Rochelle Walensky, director of the CDC, at an earlier White House briefing.
The CDC and the Biden administration have faced pressure to ease restrictions on fully vaccinated people - those who are two weeks past their last required COVID-19 dose - in part to highlight the benefits of getting the jab.
The country's aggressive vaccination campaign has paid off - US virus cases are at their lowest rate since September, deaths are at their lowest point since last April and the test positivity rate is at the lowest point since the pandemic began.
To date about 154 million Americans, more than 46 per cent of the population, have received at least one dose of a COVID-19 vaccine and more than 117 million are fully vaccinated.
The rate of new vaccinations has slowed in recent weeks, but with the authorisation on Wednesday of the Pfizer shot for children ages 12 to 15, a new burst of doses is expected in the coming days.
"All of us, let's be patient, be patient with one another," Biden said, acknowledging some Americans might be hesitant about removing their masks after more than a year of living in a pandemic that has killed more than 580,000 in the US and more than 3.3 million people worldwide.
Australian Associated Press