Expert breaks down Delta variant fueling U.S. surge in COVID-19 cases
The Delta variant of COVID-19 is running rampant in the U.S. Amid a surge in coronavirus cases, the Centers for Disease Control and Prevention is adjusting its mask-wearing guidance for vaccinated people. John Moore, a professor of microbiology and immunology at Weill Cornell Medical College, joined CBSN's Tanya Rivero to discuss.