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

  • Jason Rodriguez, right, a University of Florida Pharmacy student, gives Camila Gutierrez, 21, a junior at Florida International University from Bolivia, the Pfizer COVID-19 vaccine at the Christine E. Lynn Rehabilitation Center in Jackson Memorial hospital, Thursday, April 15, 2021, in Miami. Jackson Health System launched a COVID-19 vaccination initiative with colleges and universities in Miami-Dade County, to allow students to sign up for vaccinations through an online portal. (AP Photo/Wilfredo Lee)

  • In this April 12, 2021, file photo, Freeson Wong, 31, takes a selfie as he receives a dose of the Moderna vaccine at a vaccination center in the Chinatown neighborhood of Los Angeles. (AP Photo/Jae C. Hong, File)

  • In this March 6, 2021, file photo, boxes stand next vials of Johnson & Johnson COVID-19 vaccine in the pharmacy of National Jewish Hospital for distribution in Denver. U.S. health officials are weighing next steps as they investigate unusual blood clots in a small number of people given the vaccine — a one-dose shot that many countries hoped would help speed protection against the pandemic. (AP Photo/David Zalubowski, File)

WASHINGTON — Half of all adults in the U.S. have received at least one COVID-19 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.