Dr. Emanuel on mutations evading Covid-19 vaccines: 'It would be very, very problematic'

Former Biden transition Covid-19 advisory board member, Dr. Zeke Emanuel, joined Stephanie Ruhle to discuss the CDC's new guidance recommending indoor mask use in areas with high coronavirus transmission rates, and the possibility of mutations evading vaccine effectiveness. Savannah Mayor Van Johnson explains why he reinstated a mask mandate in his city, and NBC's Shaq Brewster, Heidi Przybyla, and Geoff Bennett report from across the country with the latest on the pandemic.