Former U.S. Food and Drug Administration (FDA) commissioner Dr. Scott Gottlieb appeared on CBS’ “Face the Nation” on Sunday where he spoke about whether those vaccinated for COVID-19 should continue to wear a mask. "If you want to add an additional measure of protection if you're in a high prevalence environment, a mask can still be helpful against this new variant,” said Gottlieb, adding wearing a mask could help protect against the highly-transmissible Delta variant of the coronavirus.