About 8% of Americans who have received one dose of either the Pfizer or Moderna vaccines have not returned for their second shot. Dr. Antony Fauci, the nation's top infectious disease expert, says important protections come from a second shot. (April 30)

      

About 8% of Americans who have received one dose of either the Pfizer or Moderna vaccines have not returned for their second shot. Dr. Antony Fauci, the nation's top infectious disease expert, says important protections come from a second shot. (April 30)