This week, we're talking about disease prevention, public health, and whether or not some types of vaccinations should be mandatory. We'll spend the hour in a panel discussion with Barry Bloom, Harvard University's Distinguished Service Professor of the Department of Immunology and Infectious Diseases, University of Toronto public health ethicist Alison Thompson, pediatrician and University of Pennsylvania vaccinology professor Paul Offit, and Nicholas Little, Vice President and General Counsel at the Center for Inquiry.