BERLIN — The first shipments of coronavirus vaccines have arrived in nations across the European Union as authorities prepared to administer the first shots to the most vulnerable people in a coordinated effort on Sunday.

The vaccines developed by BioNTech and Pfizer arrived by truck in warehouses across the continent on Friday and early Saturday after being sent from a manufacturing center in Belgium before Christmas.

The rollout marks a moment of hope for a region that includes some of the world’s earliest and worst-hit virus hot spots, including Italy and Spain, and others, like the Czech Republic, that were spared the worst early on only to see their health care systems near their breaking points in the fall.

Altogether, the 27 EU member states have seen at least 16 million cases of the coronavirus and more than 336,000 deaths.

“It’s here, the good news at Christmas,” German Health Minister Jens Spahn said at a news conference Saturday. “At this moment, trucks are underway across Europe, across Germany and its regions, to deliver the first vaccine. More deliveries will follow the day after tomorrow. This vaccine is the decisive key to end this pandemic.”