The European Union (EU) will authorize a contract for the purchase of up to 300 million doses of the COVID-19 vaccine jointly developed by German company BioNTech and its American partner Pfizer, European Commission President Ursula von der Leyen said on Tuesday.

File photo: VCG

"This is the most promising vaccine so far," she said on Twitter. The contract, due to be reached on Wednesday, will be the fourth one the EU secures with a pharmaceutical company to buy vaccines for COVID-19.

The BioNTech/Pfizer vaccine candidate has proved to be more than 90 percent effective in preventing COVID-19 infection in participants with no proven previous SARS-CoV-2 infection, the two companies announced on Monday.

As the world is struggling to contain the COVID-19 pandemic, countries including Germany, China, Russia, the United Kingdom and the United States are racing to find a vaccine.

According to the website of the World Health Organization, as of Nov. 3, there were 202 COVID-19 candidate vaccines being developed worldwide, and 47 of them were in clinical trials.