Rochelle Walensky
© Reuters / Kevin LamarqueRochelle Walensky prepares to speak at a press conference with Joe Biden in Wilmington, Delaware, December 8, 2020.
People who are fully vaccinated against COVID-19 will be able to resume domestic and overseas travel without a mandatory self-quarantine or return testing if they wear masks in public, the Centers for Disease Control and Prevention (CDC) has determined.

CDC Director Rochelle Walensky told reporters Friday that the updated guidance is based on new studies that show fully vaccinated people are unlikely to transmit the coronavirus.

"The science on COVID-19 is constantly evolving," she said.

The CDC is still advising against travel in general as the pandemic continues.

"Despite the good news on the vaccination front, we simply cannot afford to relax the prevention strategies," Walensky said.

Last month, the Biden administration faced backlash for not updating travel guidance for vaccinated people, along with updates on indoor gatherings for those who have been fully inoculated.

"When you don't have the data and you don't have the actual evidence, you've got to make a judgment call," White House chief medical adviser Dr. Anthony Fauci said during an appearance on CNN at the time, prompting some concerns that it downplayed the importance of vaccines in ending the pandemic.

More than 550,000 people in the United States have died of COVID-19 since the outbreak began last year. The United States has ramped up its vaccination efforts, with more than a million people getting shots every day.

"The science shows us that getting fully vaccinated allows you to do more things safely," Walensky said.

Three vaccines are currently approved in the United States — the Pfizer and Moderna vaccines, which have a two-shot process, and the one-shot Johnson & Johnson vaccine. "Fully vaccinated" means someone has received the required doses and two weeks have passed. Recent studies have indicated that people who are vaccinated are unlikely to carry coronavirus or infect people who are not vaccinated.

White House Press Secretary Jen Psaki told reporters Friday that the Biden administration is relying on the private sector to consider how the relaxing of restrictions for vaccinated people should be handled.

"That's a private-sector initiative and one that we expect that they would be the drivers of," she said. "It's just these are public health guidelines in terms of what is safe, and that's why the CDC updated them."

She said the administration similarly is attempting to offer guidance for facilities, including music venues and sporting events.

"They're looking for ways to figure out how they can bring people back to normal and make things normal again," she said. "We'll see what they come up with."