Explainer: How will US make more shots available by May 1?

A man receives a COVID-19 vaccine in North Las Vegas last month. President Joe Biden’s pledge that all U.S. adults will be eligible for coronavirus vaccines by May 1 is putting a new challenge in front of the nation. For that to happen, the federal government must deliver doses to hundreds of new vaccination sites and recruit more health care workers to administer the shots.

AP file photo