The EU is launching a co-ordinated vaccine rollout to fight Covid-19, in what the bloc's top official says is a "touching moment of unity", reports BBC.
European Commission President Ursula von der Leyen said on Saturday the Pfizer-BioNTech vaccine had been delivered to all 27 member states.
Some countries started administering the jabs on Saturday, saying they were not prepared to wait another day, reports BBC.
The EU has so far reported more than 335,000 Covid-related deaths.
More than 14 million people have been infected, and strict lockdown measures are currently in place in nearly all the member states.
The vaccine rollout comes as cases of the more contagious variant of Covid-19 are confirmed in several European nations as well as Canada and Japan.
News of the new variant triggered travel restrictions around the world last week.
What's the latest on the vaccine rollout?
Mass vaccination for the EU's 446 million people is due to begin in the coming hours.
This comes after the European Medicines Agency (EMA) and the European Commission authorised the German-US Pfizer-BioNTech vaccine.
The EU has secured contracts for more than two billion vaccine doses from a range of drug companies.
"Today, we start turning the page on a difficult year. The #COVID19 vaccine has been delivered to all EU countries. Vaccination will begin tomorrow across the EU," Ms von der Leyen tweeted on Saturday.
"The #EUvaccinationdays are a touching moment of unity. Vaccination is the lasting way out of the pandemic," she added.
German Health Minister Jens Spahn said on Saturday: "This really is a happy Christmas message. At this moment, lorries with the first vaccines are on the road all over Europe, all over Germany, in all federal states. Further deliveries will follow the day after tomorrow.
"This vaccine is the crucial key for defeating the pandemic. It's the key for us getting back our lives."
Italian Foreign Minister Luigi Di Maio urged his compatriots to get the jabs. "We'll get our freedom back, we'll be able to embrace again," he said.
Health workers in north-east Germany decided not to wait for Sunday and started immunising elderly residents of a nursing home in Halberstadt.
In Hungary, the first recipient of the vaccine was a doctor at Del-Pest Central Hospital on Saturday, the state news agency says.
The authorities in Slovakia also said they had begun vaccinating.