Dr. Mario Ramirez explains how drug companies' vaccine pledge leaves some wiggle room

Dr. Mario Ramirez, an ER physician and former Acting Director for the Office of Pandemic and Emerging Threats at the Department of Health and Human Services, joins Andrea Mitchell to break down a new pledge from nine pharmaceutical companies joining forces to say that they will only submit a vaccine for authorization when they have evidence of safety and efficacy.Sept. 8, 2020