Tens of thousands of people in at-risk groups will not receive their first Covid vaccine this week after the rollout of AstraZeneca was halted over blood clot fears.
Around 20,000 people with serious underlying conditions and a further 10,000 frontline healthcare workers had been due to get an AstraZeneca vaccination in the coming days However, this will now not happen.
A cluster of four people who suffered clots in Norway after being vaccinated has led to a temporary suspension of the drug’s use in Ireland.
The European Medicines Agency (EMA) has initiated an urgent review of all clotting events occurring with the vaccine to determine if there is a possible health risk.
More than 117,000 Irish people have already received a dose of the AstraZeneca vaccine and have been advised to contact their GP if they still feel ill three days after the jab or if they notice blue spots on their skin.
However, deputy chief medical officer Dr Ronan Glynn moved to reassure people who have been vaccinated, by stating that there is "no evidence of a cause and effect at this point".
"It may be nothing, we may be overreacting, and I sincerely hope that in a week's time we are accused of being overcautious," he said.
Dr Glynn said the cases highlighted in Norway were in people in their 30s and 40s and given the fact that the rollout of vaccines to younger people in high-risk categories was due to start this week, the National Immunisation Advisory Committee (NIAC) “felt that they had no option other than to make a recommendation to temporarily pause the programme”.
It comes as 384 new cases of Covid were confirmed last night. No further deaths were reported.
Health Minister Stephen Donnelly said he understood those who were due to be vaccinated will be extremely disappointed.
"Obviously, nobody would want to see this kind of thing happening. However, what I am very comforted by as Minister for Health is that our senior clinicians leading the vaccination programme moved very quickly and they are erring on the side of caution.
"That's something I want to see and I think that's something the Irish people want to see."
He added: "We will see what the EMA say in the coming days, but what we hope is that this is nothing more and a very short deferral."
Mr Donnelly said some people may view the stalling of vaccinations as an over-reaction, however, he said he would prefer that caution and safety are prioritised.
The EMA is now due to review the evidence and report later this week and Mr Donnelly hopes it will simply mean a rescheduling of people who were due to get the dose.
"If they have to be rescheduled for a week or two because of this of course they will be disappointed by that."
While the cases in Norway are concerning, the minister said there have been just 30 notifications of clots out of 5m people who have received the AstraZeneca vaccine in the EU.
Meanwhile, a spokesperson for the minister said it is has always been the advice of NIAC to wait 12 weeks to administer the second dose of AstraZeneca and this strategy was adopted by the HSE when it began rolling out the jab five weeks ago.
The spokesperson said the interval time for the Pfizer and Moderna vaccines remains four weeks.
Taoiseach Micheál Martin will discuss Ciovid and the rollout of vaccines when he speaks with US president Joe Biden to mark St Patrick's Day later this week.
However, Mr Martin said he is "not aware of too many countries that are giving their vaccines away," when he was asked if he would seek some of the tens of millions of vaccines currently in storage in the US.
"I am not pre-empting any discussion I will have in detail with the president but obviously the broader Covid vaccination issue will of course be discussed."