The Centers for Disease Control and Prevention revised its public health guidance Tuesday, saying fully vaccinated people can exercise and attend small gatherings outdoors without wearing a face mask.
People two weeks removed from their last vaccine can exercise alone or with other household members outside without a face covering, the CDC said. They can also meet outdoors with a small group of other fully vaccinated people, or a mixture of fully vaccinated and unvaccinated people, the agency added. The guidance did not say what counts as a small gathering.
Dining unmasked at an outdoor restaurant with friends from multiple households is also acceptable, according to the CDC.
The agency still recommends that fully vaccinated people wear a mask at outdoor spaces where the risk of Covid-19 is less clear. Those include sporting events, concerts, parades and other crowded places.
"In public spaces, the vaccination status of other people or whether they are at increased risk for severe COVID-19 is likely unknown," the CDC wrote in its guidance. "Therefore, fully vaccinated people should continue to follow guidance to protect themselves and others, including wearing a well-fitted mask, when indoors or in an outdoor setting or venue where masks are required."
"CDC cannot provide the specific risk level for every activity in every community, so it is important to consider your own personal situation and the risk to you, your family, and your community before venturing out without a mask," the agency added.
Some former health officials and infectious disease experts have been saying outdoor mask mandates are no longer necessary as the U.S. vaccinates more Americans.
As of Monday, more than 140 million Americans, or 42.5% of the total population, had received at least one dose of a Covid vaccine, according to data compiled by the CDC. Roughly 95.8 million Americans, or 28.9% of the population, are fully vaccinated, according to the CDC.
During a press briefing Tuesday, CDC Director Dr. Rochelle Walensky said she hopes the new guidance will encourage more Americans to get vaccinated.
"Today is another day we can take a step back to the normalcy of before," she said. "If you are fully vaccinated, things are much safer for you than those who are not fully vaccinated."
Walensky declined to define a "small gathering." She said it was difficult to provide an exact number because it depends on the size of the space for gathering, the space between people and the amount of ventilation.
The announcement from the CDC comes just ahead of Memorial Day and Fourth of July parade season. President Joe Biden has said he hopes to see enough Americans vaccinated by Independence Day to safely hold small outdoor gatherings.
On Tuesday, Biden touted the CDC guidance, saying vaccinated people can now go to the park or a picnic with friends unmasked. He cited the loosened restrictions as a reason to get vaccinated, but stressed that Americans should still wear masks in more crowded outdoor settings.
"I want to be clear: If you're in a crowd like a stadium or at a concert, you still need to wear a mask, even if you're outside," he said in a speech on North Lawn at the White House.
Dr. Scott Gottlieb, a former Food and Drug Administration commissioner, told CNBC on Monday that public health officials should take a more relaxed stance on outdoor activities in general because vaccination levels in the U.S. are driving down new infections.
Officials should take steps "to allow more gatherings outside, allow more large groups, allow sporting events, things of that nature," he told "Squawk Box." "The weather is warming up. We have the opportunity to bring more activities outside. We know activities outside are lower risk than things done indoors."
Dr. Isaac Bogoch, an infectious disease specialist at the University of Toronto, said Monday he supported the anticipated guidance. He said that more research is showing that few Covid infections happen outdoors.
He added that masks should still be mandated in indoor settings until most of the U.S. population is vaccinated and that it is difficult for the virus to spread from one person to another.
The CDC also said unvaccinated people can exercise alone or with a household member without a mask. It still recommends vaccinated people wear masks in places such as hair salons, shopping malls, museums, movie theaters and houses of worship.
"It's been over a year. We have a very good understanding of who gets infected and how they get infected," he told CNBC in a phone interview. "I think it's fair to say you don't need to wear a mask outside unless you can't maintain 2 meters or 6 feet of social distancing."
Over the weekend, White House chief medical advisor Dr. Anthony Fauci indicated that the new mask guidance was imminent, but also warned that Americans should adhere to public health measures until the CDC makes an assessment.
"What I believe you're going to be hearing, what the country is going to be hearing soon, is updated guidelines from the CDC," Fauci told ABC's Sunday program "This Week With George Stephanopoulos." "The CDC is a science-based organization. They don't want to make any guidelines unless they look at the data and the data backs it up."