The jab, developed with Oxford University, will not be used in Ireland and the Netherlands for now.
People across the UK have been urged to get their coronavirus vaccine, despite a growing list of countries temporarily suspending use of the AstraZeneca jab amid concern around blood clots.
The vaccine’s manufacturer has insisted it is safe, saying a review of available data in more than 17 million people who have been vaccinated across the UK and EU has shown no evidence of an increased risk.
After Ireland announced on Sunday that it was suspending use of the jabs as a “precautionary step”, the UK’s medicines regulator said the available evidence “does not suggest the vaccine is the cause” of clots.
Dr Phil Bryan, vaccines safety lead at the Medicines and Healthcare products Regulatory Agency (MHRA), said people “should still go and get their Covid-19 vaccine when asked to do so.”
Northern Ireland’s department of health said the rollout there will continue, “in line with MHRA guidance”.
The Republic’s health minister Stephen Donnelly said use of the Oxford/AstraZeneca jab was being temporarily suspended “based on new information from Norway”.
The decision followed reports of serious clotting in adults in Norway which left four people in hospital.
The Netherlands also said on Sunday that it was suspending use of the vaccinations as a precaution for two weeks.
Several other European countries have already temporarily suspended use of the jabs.
But, the head of the Oxford University vaccine group has sought to reassure the public over its Covid-19 jab.
Professor Andrew Pollard said that while it was right that regulators investigated reports of blood clots in people who have had the vaccine, data from millions of people was 'very reassuring' that there was no link.
He said 'safety is clearly absolutely paramount' but that about 3,000 cases of blood clots occur every month in the UK from other causes.
'So, when you then put a vaccination campaign on top of that, clearly those blood clots still happen and you’ve got to then try and separate out whether, when they occur, they are at all related to the vaccine or not,' he told BBC Radio 4’s Today programme.
Prof Pollard said that more than 11 million doses have now been given in the UK, and the MHRA has said 'very clearly that they’re not seeing any increase in the number of cases of blood clots' over what they would see normally.
'I think at this moment we’ve got the most data from the UK, which looks very reassuring, but of course it’s absolutely right that there’s careful monitoring of safety and this gets looked into,' he added.
Meanwhile, European Medicines Agency (EMA) has said the vaccine’s benefits continue to outweigh its risks and that jabs can keep being administered while it carries out a review into any incidents of blood clots – noting last week that there had only been 30 cases reported among almost five million people jabbed in the European Economic Area.
The number of cases of blood clots reported is lower than the hundreds of cases that would be expected among the general population, AstraZeneca’s chief medical officer Ann Taylor said.
The pharmaceutical giant said its review had found no evidence of an increased risk of pulmonary embolism, deep vein thrombosis (DVT) or thrombocytopenia, in any defined age group, gender, batch or in any particular country.
Dr Taylor said: “Around 17 million people in the EU and UK have now received our vaccine, and the number of cases of blood clots reported in this group is lower than the hundreds of cases that would be expected among the general population.
“The nature of the pandemic has led to increased attention in individual cases and we are going beyond the standard practices for safety monitoring of licensed medicines in reporting vaccine events, to ensure public safety.”
Dr Bryan said: “We are aware of the action in Ireland.
“We are closely reviewing reports but given the large number of doses administered, and the frequency at which blood clots can occur naturally, the evidence available does not suggest the vaccine is the cause.
“People should still go and get their Covid-19 vaccine when asked to do so.”