The European Medicines Authority (EMA) will try to reach a decision on the approval of Moderna’s COVID-19 vaccine on Wednesday, after failing to take a decision two days earlier.

The EMA’s human medicines committee (CHMP) had called an unscheduled meeting Monday afternoon to discuss Moderna’s vaccine, but failed to reach a conclusion then.

The medicines regulator did not specify why it could not yet approve the vaccine, but on Tuesday said its experts were “working hard to clarify outstanding issues with the company”.

The Dutch national medicines authority told Reuters it was preparing for both a positive decision on Wednesday and for a scenario in which a conclusion still could not be reached.

The EMA has set a Jan. 12 deadline for whether to recommend Moderna’s vaccine. It recommended a COVID-19 vaccine from Pfizer and its German partner BioNTech on Dec. 21.

Distribution of the Moderna vaccine has already begun in Canada and the United States. Israel was the first country outside North America to grant authorisation.