There is mounting speculation that many of the doses ordered from Pfizer and AstraZeneca by the EU were instead directed to the UK from a Belgian factory.
This, it now emerges, has sparked an official probe by regulators in Belgium.
A first visit by officials from the Belgian federal medicines agency was completed on Wednesday at the site in Seneffe, Hainaut, the Belgian health ministry has confirmed.
The inspection was requested by the Commission.
The AstraZeneca vaccine, approved by the UK some weeks ago, is finally expected to be authorised by the European Medicines Agency on Friday.
The bitter vaccines row between the EU and UK comes after a year of tense negotiations over post-Brexit trade and security.
The EU institutions and 27 EU governments are coming under severe criticism for the slow deployment of their vaccination programme.
The UK, meanwhile, has administered vaccine first doses to more than 10 percent of adults and plans to vaccinate the most vulnerable 15 million - including all over-70s - by mid-February. The EU has reached 2 percent so far.
“The contract with AstraZeneca includes its factories in the UK and we expect that we can and will get doses of the vaccine from these series of plants mentioned in the contract. This includes those sites in the UK”
European Commission spokesman
The UK’s regulator approved the Oxford/AstraZeneca vaccine in late December.
The company has told the UK it will produce 2m doses a week of the vaccine for the UK in order to successfully fulfil a total order of 100m jabs, but it will only be able to deliver to EU Member States about 25 percent of the 100m doses expected by the end of March.
The UK has been accused of a “me first” approach to the vaccine rollout but the EU has also come under fire for its strategy.
On Thursday, a Commission spokesman was quizzed about the escalating row and the EU’s vaccine strategy at a midday press briefing.
The spokesman also confirmed that the EU had now ordered 200m doses of vaccines produced by the American pharma company, Johnson and Johnson, with the option to buy another 200m doses.
He told reporters, “As with the other advance purchasing agreements we have concluded there are clear delivery schedules at certain moments in time and the Johnson and Johnson agreement is also bound by this.”
On the ongoing row about the AstraZeneca vaccine, he said, “We have written to AstraZeneca telling them of our intention to publish the contract the EU signed with them.”
“We intend to continue working with AstraZeneca in order to solve outstanding issues. We are in contact with the company to find a solution so that the EU receives the doses as foreseen under the contract signed with them.”
“The contract with AstraZeneca includes its factories in the UK and we expect that we can and will get doses of the vaccine from these series of plants mentioned in the contract. This includes those sites in the UK.”
“It is our aim to make the contract public and we are in contact with AstraZeneca in order to ensure this and trust that it will be done in line with the contract because EU citizens need vaccines.”
It is believed AstraZeneca has two plants in the UK and two in EU countries.
The Commission spokesman said, “The Belgian authorities have inspected one of the Belgian plants run by AstraZeneca, but we cannot say why or comment further on this.”
Meanwhile, the Commission announced on Thursday that is has adopted “guidelines on proof of vaccination for medical purposes.”
It says these guidelines aim to “support the interoperability of vaccination certificates, meaning the contents of the vaccination certificates is uniform, and establish a minimum dataset for each certificate.”
Stella Kyriakides, Commissioner for Health and Food Safety, said: “I welcome the adoption of the guidelines on the proof of vaccination for medical purposes.”
She added, “We need a common approach to vaccination certificates, and I am looking forward to continuing cooperation with the World Health Organization to scale up this tool at a global level.”
“Interoperable vaccination certificates will be an important tool for citizens during the pandemic but also after we have overcome it.”