The Delta variant is continuing its deadly march -- particularly among those who haven’t been vaccinated. It’s also draining the optimism of only a few months ago that the U.S. had turned the corner on COVID-19. For perspective, we look back to the far deadlier influenza pandemic of 1918: how it started; how it was treated; how it divided people; how it ended; and what it helped create. Laura Spinney, author of Pale Rider: The Spanish Flu of 1918, and How it Changed the World joins Josh Robin to discuss the parallels.