The 27-nation bloc, with a population of 450 million, has booked more than 1 billion doses of potential COVID-19 vaccines from three drugmakers. It is negotiating the advance purchase of another billion vials with other companies.
"There will not be sufficient doses of COVID-19 vaccines for the entire population before the end of 2021," a European Commission official told diplomats from EU states in a closed-door meeting on Monday, a person who attended it told Reuters.
A second official confirmed the statement. An EU Commission spokesman was not immediately available for comment.
The EU Commission had earlier said vaccines will be limited "during the initial stages of deployment" but had never clarified how long the initial phase would last.
There is still no effective COVID-19 vaccine, but the first shots could be available at the beginning of next year, the Commission said earlier in October.
Given a likely limited supply, the Commission has for months urged EU governments to devise vaccination plans that would prioritise vulnerable and essential groups, such as healthcare workers, the elderly or people with chronic diseases.
But apart from a consensus on inoculating doctors and nurses, "there is no common line on other groups," the Commission official said at the internal meeting this week.
In July a paper agreed by the Commission and EU governments said at least 40% of the EU population should be vaccinated in the first phase.
Some EU countries want to book doses for their entire population with the aim of rolling them out already by mid-2021.
A third EU official said this bold goal could be achieved if the EU reached supply deals with at least seven vaccine candidates.
The EU has so far secured doses of the potential vaccines being developed by AstraZeneca, Sanofi and Johnson & Johnson. It has also said it is in talks with Moderna, Pfizer and CureVac.
(Reporting by Francesco Guarascio @fraguarascio, Editing by William Maclean and Alexandra Hudson)
By Francesco Guarascio