During a May 13 White House COVID briefing, CDC Director Rochelle Walensky, MD, was asked whether fully vaccinated people could take their masks off even when surrounded by people they don’t know are vaccinated, like at a concert. Walensky said that per the new CDC guidelines, they can.ae0fcc31ae342fd3a1346ebb1f342fcb “The science demonstrates that if you are fully vaccinated, you are protected,” Walensky explained. “It is the people who are not fully vaccinated in those settings, who might not be wearing a mask, who are not protected. Those [are the] people that we are encouraging to get vaccinated and to wear a mask and to physically distance.” The CDC director added that in a situation like this, fully vaccinated individuals “could wear a mask” if they wanted to. “But we are saying in those settings, based on the science, that it is safe [not to],” she said, doubling down on the idea of vaccinated people ditching their masks at a concert. However, not all experts seem to agree with the CDC on this new stance. The New York Times surveyed 723 U.S. epidemiologist to ask about mask wearing during certain activities now that more than 118 million people in the U.S. are fully vaccinated against COVID. Of the epidemiologists surveyed, 88 percent (or 636) said that they felt it was still necessary to wear masks when outside in a large crowd—like at an outdoor concert or a protest—even if you’re vaccinated. For unvaccinated people, 99 percent of epidemiologists said you should still wear a mask in these situations. “Vaccinated people are quite safe,” Maria Glymour, MS, an epidemiologist at the University of California, San Francisco, told the NYT. “If you know everyone’s vaccinated, it’s OK. I’d just worry that with a large group, you of course cannot know that.” RELATED: For more up-to-date information, sign up for our daily newsletter. As the CDC notes, the vaccines are not 100 percent effective and fully vaccinated individuals can still get infected with the coronavirus—though the risk is “extremely low,” White House COVID adviser Anthony Fauci, MD, said during the May 13 briefing. “A small percentage of people who are fully vaccinated will still get COVID-19 if they are exposed to the virus that causes it. These are called ‘vaccine breakthrough cases,’” the CDC states on its website. According to the NYT, because vaccines are not 100 percent effective, they have more chances to fall short the more people you’re surrounded by, especially if you don’t know their vaccination status. Many of these epidemiologists told the news outlet that they would hesitate to take masks off in every situation until more people are vaccinated. “There is a strong likelihood that we will experience unexpected problems due to moving about as if the COVID pandemic was no longer a threat,” Jana Mossey, PhD, an epidemiologist who retired from Drexel University, told the NYT. And for an update from the U.S.’s top health agency on breakthrough infections, The CDC Says People Who Get COVID After Vaccination Have This in Common.