The US Centers for Disease Control and Prevention (CDC) has announced that fully vaccinated Americans do not need to wear a mask when they are outdoors.
Those who have received all required jabs can ditch their face coverings if alone or in small groups of vaccinated people, the new guidelines say.
But the CDC left in place its guidance to don a mask indoors and in crowded settings or venues.
Over 95 million Americans have been fully vaccinated thus far.
Following the CDC announcement on Tuesday, President Joe Biden celebrated the new guidance as “extraordinary progress”.
“Our scientists are convinced by the data that the odds of getting or giving the virus to others is very, very low,” Mr Biden said. “The bottom line is clear: if you’re vaccinated you can do more.”
The president also urged Americans who have not yet received their shot to do so, calling it a “patriotic” act.
“Vaccines are about saving your life but also the lives of the people around you – but they’re also about helping us get back closer to more normal living.”
Health officials presented the new safety guidelines at Tuesday’s White House coronavirus task force briefing.
“Small- and medium-sized gatherings for people who are outside and vaccinated can safely be done without a mask,” said CDC director Dr Rochelle Walensky. This includes exercising or dining outdoors.
She said that determining whether to wear a mask in larger outdoor gatherings would depend on other concerns like how well-ventilated a venue is and how much space is left between people.
The guidelines are for the fully vaccinated – which means two weeks after a person’s final vaccine jab.
Evidence suggests that, although Covid-19 infections can happen outdoors, the risks of transmission are very low. Early studies also indicate that fully vaccinated people are much less likely to spread the virus.
Dr Walensky said mask guidance for the fully vaccinated was intended largely “to protect the unvaccinated”.
“We really do want people who are unvaccinated to limit interactions with people, to go back to the basic principles of increased ventilation, spacing,” she said.
Health officials have noted that the case count in the US is stabilising as the rate of vaccinations continues to grow, and on Tuesday, they called for more people to sign up for vaccinations.
Nearly 141 million Americans – about 42% of the total population – have received at least one vaccine dose as of 26 April, according to the CDC.