Many top scientists say a coronavirus vaccine could be ready before the end of the year, and President Trump has even said it could happen by Election Day. But it's a very challenging process CBS News' Natalie Brand reports on the latest developments, and Elaine Quijano of CBSN's "Red & Blue" discussed that deadline and how scientists conduct clinical trials with Dr. Wilbur Chen, associate professor of medicine at the University of Maryland, and chief of the Adult Clinical Studies Section within the Center for Vaccine Development and Global Health.
