April 27 (UPI) -- Fully vaccinated Americans don't need to wear masks outdoors if they're walking, running or biking, or if they attend small outdoor gatherings with friends, federal health officials announced Tuesday.
The guidance from the Centers for Disease Control and Prevention also said vaccinated adults should continue wearing masks and staying 6 feet apart in large public spaces, such as sports events, indoor shopping malls and movie theaters. Those venues could include people whose vaccination and health status related to COVID-19 are unknown.
The CDC guidance also said unvaccinated individuals can go without masks outside when walking, jogging or biking outdoors with household members. But health officials added that did not include crowded outdoor settings.
Even vaccinated Americans should avoid crowds, medium and large gatherings, and poorly ventilated spaces, health officials said. The CDC considers people to be fully vaccinated when they are two weeks past their final shot.
President Joe Biden spoke on the new guidance during a news conference on the North Lawn of the White House. He wore a mask while walking outdoors to the podium, but kept it off while walking back to the White House until he returned indoors.
"The CDC is able to make this announcement because our scientists are convinced by the data that the odds of getting or giving the virus to others is very, very low, if you've both been fully vaccinated and out in the open air," he said.
Biden also thanked people who have been vaccinated for doing their "patriotic duty" to protect others.
"The vaccines are about saving your life but also the lives of the people around you," he said. "But they're also about helping you get us get back to closer to normal and our living more normal lives, getting together with friends, going to the park for a picnic without needing a mask."
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and Biden's chief medical adviser, said Monday that "the risk of infection outside is really minimum."
"If you're vaccinated, and you're outside, it's even less," he said during a virtual event hosted by the Harvard T.H. Chan School of Public Health.
The Journal of Infectious Diseases reported in a study last fall that the possibility of viral transmission is 18 times greater indoors than outdoors. Less than 10% of COVID-19 infections occurred outside, it noted.
A turning point in the pandemic could be reached within a few weeks, Fauci also said.
On Sunday, the United States reported a 14% decline in the seven-day average of new COVID-19 cases per day, according to a CNBC analysis of Johns Hopkins University data. Fauci said there have been about 3 million vaccinations per day.
Fauci said the Biden administration's goal is to vaccinate between 230 million and 280 million people to achieve herd immunity -- which he said would be more than 70% of the U.S. population. He called herd immunity a "moving target."
"If you're waiting for classic measles-like herd immunity, that's going to be a while before we get there," Fauci said, according to CNBC.
Last week, Biden called on businesses to give workers paid leave so they can get vaccinated and said his goal of 200 million vaccinations within his first 100 days had been reached.