Half of US adults have received at least one COVID-19 shot

FILE-This Thursday, April 8, 2021 file photo shows Kent State University student Regan Raeth of Hudson, Ohio, has her COVID-19 vaccination administered by Kent State nurse Kristen Barath in Kent, Ohio. (AP Photo/Phil Long, File)

A Northwell Health nurse inoculates Local 28 Sheet Metal Worker Demetrius Buttelman with the first dose of the Pfizer vaccine Wednesday, April 14, 2021 at Belmont Park in Elmont, N.Y.(AP Photo/Mary Altaffer, Pool)

Local 28 Sheet Metal Worker Demetrius Buttelman gestures after being inoculated with the first dose of the Pfizer vaccine Wednesday, April 14, 2021 at Belmont Park in Elmont, N.Y. (AP Photo/Mary Altaffer, Pool)

WASHINGTON — Half of all adults in the U.S. have received at least one COVID-19 vaccine shot, the government announced Sunday, marking another milestone in the nation’s largest-ever vaccination campaign but leaving more work to do to convince skeptical Americans to roll up their sleeves.