AstraZeneca says trial data from U.S. study on its COVID-19 vaccine shows it's 79% effective
AstraZeneca says advanced trial data from a U.S. study on the COVID-19 vaccine it developed along with Oxford University shows it is 79% effective in preventing symptomatic illness and 100% effective against severe illness and hospitalization. Dr. David Agus joined "CBS This Morning" to explain more.