BRUSSELS, Dec. 17 (Xinhua) -- The European Union (EU) will start vaccination for COVID-19 after Christmas, the bloc's executive chief Ursula von der Leyen announced on Thursday.

"It's Europe's moment. On 27, 28 and 29 December vaccination will start across the EU," von der Leyen tweeted.

The announcement came two days after the European Medicines Agency (EMA) decided to bring forward a meeting to conclude its assessment of the vaccine jointly developed by Germany's BioNTech and America's Pfizer.

On Thursday, French President Emmanuel Macron tested positive for COVID-19, and a number of EU leaders including European Council President Charles Michel, Spanish Prime Minister Pedro Sanchez, as well as Secretary-General of the Organization for Economic Co-operation and Development (OECD) Angel Gurria went into self-quarantine after having lunch with Macron one day earlier.

According to the website of the World Health Organization, as of Wednesday, there were 222 COVID-19 candidate vaccines being developed worldwide, and 56 of them were in clinical trials.