BRUSSELS (REUTERS, BLOOMBERG) - The European Union failed to make a breakthrough in crisis talks with AstraZeneca on Wednesday (Jan 27) and demanded the drugmaker spell out how it would supply the bloc with reserved doses of Covid-19 vaccine from plants in Europe and Britain.

The EU is making more comprehensive checks on vaccines before approval, which means a slower roll-out of shots than former EU member Britain and growing public frustration.

The issue has been exacerbated by Anglo-Swedish AstraZeneca and Pfizer of the United States both announcing delivery hold-ups in recent weeks.

"We regret the continued lack of clarity on the delivery schedule and request a clear plan from AstraZeneca for the fast delivery of the quantity of vaccines that we reserved for Q1," EU Health Commissioner Stella Kyriakides said in a tweet.

"We will work with the company to find solutions and deliver vaccines rapidly for EU citizens," she said, after AstraZeneca chief executive Pascal Soriot addressed a vaccine body made up of representatives from the EU's 27 members.

The Anglo-Swedish drugmaker has refused to cave to demands that it take vaccine supplies from its UK factories to increase doses going to the bloc.

The root of the dispute is Astra's decision to prioritise the UK over the EU following a Belgian production glitch, in what Brussels claims to be a breach of contractual commitments. The two sides spoke on Wednesday evening and held their ground with another meeting expected.

AstraZeneca said in a statement it had a constructive conversation with the EU about the complexities of scaling up production and had committed to closer coordination on working out deliveries in the coming months.

Earlier, Ms Kyriakides told a news conference that two of the four factories from which AstraZeneca has committed to providing vaccines to the EU are in Britain.

British Prime Minister Boris Johnson said it would have been a "great pity" if the United Kingdom had stayed in the European Union's vaccine programme rather than set up its own plan.

"I do think that we've been able to do things differently, and better, in some ways," he said in Parliament.

AstraZeneca, which partnered with Britain's Oxford University to develop its vaccine, said last week it would cut supplies to the EU in the first quarter, with an EU official saying that meant the EU would receive 31 million doses in the period, or 60 per cent less than initially agreed, due to production issues at a Belgian factory.

The EU has been pushing the company for a week to revise these cuts, but it is unclear how it can force delivery of the agreed amounts.

Mr Soriot told newspapers on Tuesday the EU contract was based on a best-effort clause and did not commit the company to a specific timetable for deliveries.

He said that vaccines meant for the EU were produced in four plants in Belgium, the Netherlands, Germany and Italy.

But EU Commission officials said on Wednesday that the contract stipulated that the company had also committed to providing vaccines from two factories in Britain.

They added the firm had not provided sufficient explanations on why doses could not be shipped from stocks at fully functioning factories.

Reuters on Tuesday exclusively reported that EU's calls to reroute doses from Britain had not been answered by AstraZeneca .

As an example of how the glitches are biting, delays in deliveries are forcing health authorities in Spain's wealthiest regions of Madrid and Catalonia to restrict inoculations even as a third wave of contagion rages, officials said.

Adding to the confusion, a factory in Wales that produces AstraZeneca's vaccine was partially evacuated on Wednesday after it received a suspicious package and police said a bomb disposal unit was dealing with the incident.

Meeting or no meeting?

The EU has also threatened to monitor future exports of Covid-19 vaccines, although the EU trade commissioner ruled out any export bans.

Fraught relations showed up in confusion about the timing of a meeting between the EU and AstraZeneca and whether the company would even attend.

Having delivered just 2.2 shots for every 100 people, the EU lags way behind both the United States and the United Kingdom, and is several months away from immunising a sufficient number of people to allow a return to normalcy.

The European Commission last year signed an advance purchase agreement with Astra for as many as 400 million Covid-19 vaccine doses - part of a total 2.3 billion doses secured so far for the EU. The AstraZeneca jab may get the EU regulatory green light by the end of this week following the bloc's approval of Pfizer-BioNTech and Moderna vaccines.

The dispute could also reverberate across the world, as governments race to stop the spread of the pandemic, before a multiplying number of mutations renders vaccines less effective against Covid-19.

"Contractual obligations must be met, vaccines must be delivered to EU citizens," Ms Kyriakides said.

While the EU is also unhappy about a lack of a schedule by AstraZeneca for vaccine deliveries beyond March, the bloc's priority is to get a rollout plan from the company specifically for the first quarter, according to a European official, who said the goal is to reach a solution rapidly.

Officials added that the best-effort clause was standard in contracts with manufacturers of products in development. One EU official said best effort meant the company had to show an overall effort to develop and deliver vaccines.

AstraZeneca said on Wednesday that supply chains were developed with input from specific countries or international organisations and that each supply chain was dedicated to the relevant countries or regions, making use of local manufacturing where possible.