Prime Minister Boris Johnson is expected to speak to his EU counterparts this week amid a row over Covid vaccine supplies continues.

EU leaders are expected to discuss a ban on Oxford-AstraZeneca vaccine exports to the UK, with the European Commission president said that the EU can "forbid" vaccines made on the continent from being sent to the UK.

The issue is around claims from the EU that the current arrangements are slowing down its own vaccine rollout with issues raised over the distribution of doses made in a Dutch factory.

But how can an export ban be put in place and how would it impact? Here's what you need to know.

What is the row about?

European Commission president Ursula von der Leyen threatened to block exports of jabs from the EU to countries with higher vaccination rates that do not offer reciprocal supplies of vaccine.

Under pressure over the bloc’s vaccine rollout, she ramped up the rhetoric this weekend, saying the EU has the power to “forbid” exports, adding: “That is the message to AstraZeneca.”

READ MORE: Coronavirus: EU threatens AstraZeneca with export ban

Less than 12% of the EU's population is reported to have received the vaccine, compared with almost 50% in the UK.

European Commission spokesperson Eric Mamer insisted that Brussels was not seeking to ban vaccine exports, but simply for manufacturers to meet their promises to the bloc. 

The Herald:

Why have these proposals been put forward by the EU?

The warning from the EU reflects growing frustration on the continent that the bloc is not getting the supplies it expected from AstraZeneca. 

But the British-Swedish manufacturer has previously maintained that because the bloc signed its contract later than the UK, EU manufacturing facilities were still catching up.

How could this affect the UK’s vaccine supplies?

Around 10 million doses of vaccine, mainly the BioNTech/Pfizer jab, have crossed the English Channel to the UK. This has been an issue with the EU with Brussels complaining that the EU is still waiting for vaccine exports from the UK. Ursula von der Leyen wanred the bloc "will reflect whether exports to countries who have higher vaccination rates than us are still proportionate".

Reports have suggested the latest focus of the row is on AstraZeneca vaccines produced in the Halix plant in the Netherlands, with officials arguing they should be kept for the EU rather than allowed to be exported to the UK.

Can the EU actually introduce an export ban?

The EU has been vocal in sending a message directly to AstraZeneca. Mrs von der Leyen warned the bloc has the power to "forbid" exports.

Article 122 of the EU treaty allows such a measure such as an export ban to be taken "if severe difficulties arise in the supply of certain products". In theory, those measures could include export bans and the waiving of patent and intellectual property rights on vaccines.

The Herald:

How is the rollout progressing in the EU and UK?

Just over 10% of adults have received a first dose of a coronavirus vaccine across the EU, according to the European Centre for Disease Prevention and Control, while in the UK, the figure is now over 50%.

Downing Street has previously said that it does not believe that vaccine supply issues will affect the current road map for easing lockdown restrictions.

What has the UK said about the row?

Defence Secretary Ben Wallace hit back on Sunday by warning that the manufacture of the Pfizer vaccine depends on supplies from the UK, amid reports its production requires lipid ingredients shipped from Yorkshire.

He told BBC One’s The Andrew Marr Show: “The grown-up thing would be for the European Commission and some of the European leaders to not indulge in rhetoric but to recognise the obligations that we all have.”

READ MORE: Ben Wallace calls any attempt from EU to block vaccine exports “counterproductive"

Helen Whately, health and social care minister told BBC Breakfast that the UK was on track to meet its target on vaccines for the top nine priority groups. 

Have there been other disputes over vaccines?

In January, the EU briefly attempted to trigger Article 16 of the Northern Ireland Protocol of the Brexit Withdrawal Agreement to impose controls on vaccines.

But Brussels backtracked after coming in for widespread criticism over the move from London, Dublin and Belfast, which came as EU chiefs faced increasing pressure over delays to the rollout of its vaccination programme.