CDC Director Dr. Rochelle Walensky, in a call with reporters, said wearing a mask is one of several everyday precautions that people can take to reduce their chances of catching or spreading a respiratory virus during the busy holiday season."We would encourage all of those preventive measures — hand washing, staying home when you're sick, masking, increased ventilation — during respiratory virus season, but especially in areas of high Covid-19 community levels."About 5% of the U.S. population lives in counties where the CDC is officially recommending masks due to high Covid levels."I want to emphasize that the flu vaccine can be life saving and importantly, there's still time to get vaccinated to be protected against flu this season and its potential serious consequences," Walensky said.More than 19,000 people were hospitalized with the flu during the week ending Nov. 26, nearly double the previous week, according to CDC data."