The jab is expected to be approved for use in the EU this week.
The EU will demand AstraZeneca provides greater detail on its distribution and delivery plan for member states when they meet later.
The drug-maker had said deliveries would be reduced by 60 per cent over the next two months.
But it was accused of giving a poor explanation for the decision when both sides spoke earlier this week.
Meanwhile, the European Medicines Agency says it hopes to be able to give the vaccine EU approval by the end of the week.
Immunology Professor at Trinity College Dublin, Mullingar's Kingston Mills, says producing large amounts of vaccine with live virus can be difficult:
Professor Mills says a delay in delivery will impact our vaccination programme:
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