The US FDA issued emergency use authorization late Friday to Pfizer and BioNTech’s COVID-19 vaccine. On Monday, the first doses were administered to US healthcare workers and nursing home residents, according to ABC News, which noted 2.9 million doses of the vaccine were shipped to 636 sites across the country.

A critical care nurse from Northwell Long Island Jewish Medical Center was vaccinated at 9:23 a.m. during a livestreamed event with New York Gov. Andrew Cuomo. “You didn’t flinch,” Cuomo said.

The University of Louisville Hospital in Kentucky will receive its first delivery of the vaccine at 9:30 a.m. and at 10:30 a.m., three doctors and two nurses will receive the vaccine.

Other locations in Connecticut, New York, Iowa, Washington, DC, and Michigan are also expected to administer vaccine doses on Monday.