We know that Americans in blue states are getting vaccinated at higher rates than those in red ones. But that gap obscures another growing divide in America's vaccine campaign — the divide within states between rural and urban areas. An NPR analysis of county-level data from the Centers for Disease Control and Prevention reveals that divide exists across age groups in almost every state. NPR's Austin Fast explains why. The Biden administration says it's making progress on closing the gap. Their focus is on getting as many people vaccinated as possible. But public health officials tell NPR's Geoff Brumfiel that the U.S. may never reach 'herd immunity.' Additional reporting in this episode from Veronica Zaragovia of member station WLRN in Miami. In participating regions, you'll also hear a local news segment that will help you make sense of what's going on in your community.Email us at considerthis@npr.org.