The Centers for Disease Control and Prevention and the Food and Drug Administration announced a recommended pause in use of Johnson & Johnson's single-use COVID-19 vaccine, while the agencies investigate reports of a rare but serious blood clot in six people. The pause comes at a time when public health officials face the growing challenge of vaccine hesitancy, as NPR's Geoff Brumfiel reports. NPR's Tamara Keith and Pien Huang explain the science behind the pause, and how it's occurring at a challenging moment for the Biden administration. Additional reporting in this episode comes from NPR's Allison Aubrey. The NPR Politics Podcast is also covering the Johnson & Johnson vaccine pause. Listen on Spotify or Apple Podcasts.In participating regions, you'll also hear from local journalists about what's happening in your community.Email us at firstname.lastname@example.org.