It has been two years since the coronavirus that causes COVID-19 entered the human population, and the world has marked another grim milestone: the death toll has surpassed more than 5 million people. That figure includes more than 750,000 Americans, of whom roughly 100,000 have died in the past three months despite the availability of safe, effective vaccines and boosters. Soon, however, Americans may reach the post-pandemic phase of this nightmarish saga. That is because herd immunity may be on the horizon, according to historian John Barry, the author of "The Great Influenza: The Story of the Deadliest Pandemic in History." In this episode, Barry explains why at least 90 percent of the U.S. population could soon have at least some immunity to the deadly virus, and what "life after COVID" might look like.