Drug giant AstraZeneca warned on Friday that it would not immediately be able to supply as many coronary vaccines to Europe as originally calculated.
According to the British company, the reason for the supply difficulties is "reduced production in production facilities belonging to the European production chain".
However, the company says it will be able to deliver millions of doses of vaccine to Europe immediately and aims to accelerate its production in February and March.
It was not immediately clear how many vaccines AstraZeneca was to supply to the EU once the vaccine was approved.
A possible EU approval for the vaccine, developed by the company in collaboration with Oxford University, is due on 29 January.
According to a Reuters EU source, deliveries would be cut by as much as 60 percent during the first quarter.
According to the news agency, the EU would receive only 31 million doses instead of the previously expected 80 million doses.
According to a Reuters source, it was also uncertain whether AstraZeneca would be able to deliver 80 million doses even in the second quarter.
According to Reuters, the company has had to cut deliveries due to production problems at a Belgian plant run by pharmaceutical company partner Novasep.
The EU has ordered a total of two billion doses of vaccine from various companies, which it has calculated well enough to vaccinate the Union's 450 million inhabitants with two vaccine spikes, if all vaccines are approved.
The EU aims to have 70% of adults vaccinated by the end of August.