The EU medicines watchdog said it could decide later on Monday whether to authorise Moderna's coronavirus vaccine, bringing forward the date from Wednesday.
The Amsterdam-based European Medicines Agency had already fast-tracked the decision from the originally scheduled date of January 12 under pressure from EU countries as infections soar.
"There is a meeting of EMA's human medicines committee (CHMP) today, Monday, 4 January, to discuss the Moderna vaccine," the regulator said.
The EMA said it would issue a statement as soon as possible "in the event that the CHMP reaches an opinion at today's meeting".
If it failed to make a decision on a year-long conditional marketing authorisation for the Moderna vaccine it would meet again on Wednesday, it added.
US-based Moderna's jab was found to be 94.1 percent effective in preventing COVID-19 compared to a placebo, in a clinical trial of 30,400 people.
The Moderna vaccine would be the second to be approved for the EU, after the EMA gave the green light for the Pfizer/BioNTech jab in another fast-tracked decision on December 21.
However the EMA said last week that the coronavirus vaccine developed by AstraZeneca and Oxford University, which was approved Wednesday in Britain, is unlikely to get a green light in the EU in the next month.
With Britain and the United States each having pushed through emergency authorisation of two vaccines, the EMA has been under pressure to speed up its regulatory process, notably from Germany.
The EMA moved from London to Amsterdam after Brexit.
© 2021 AFP