The first Phase 3 clinical trial of a Covid-19 vaccine in the United States has begun. Dr. Anthony Fauci told CNN's Wolf Blitzer how that vaccine may be prioritized once it is fully developed. The investigational vaccine was developed by the biotechnology company Moderna and the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health. The trial is to be conducted at nearly 100 US research sites, according to Moderna. The first patient was dosed at a site in Savannah, Georgia. #CNN #News