Ireland's vaccine roll-out has been hit by a delay to the Johnson & Johnson vaccines announced today and the impact of yesterday's changes to the use of the AstraZeneca jab here.
The Johnson & Johnson vaccine was recently described as a "game changer" for Ireland by Taoiseach Micheál Martin.
Ireland has ordered 2.2 million doses, with 600,000 due between now and later in June.
Being a single-dose vaccine it is viewed as particularly useful.
But the latest news that the US has paused its roll-out, to investigate rare blood clots, is a setback.
The hope is it will be a temporary pause.
But the company has also delayed the roll-out of the vaccine in Europe as a result.
The Johnson & Johnson vaccine is made using the same technology as the AstraZeneca vaccine. It's called non-replicating viral vector.
The first batches of the Johnson & Johnson jab only arrived in Europe this week and Ireland was due to get around 40,000 doses within days.
But that has now been replaced with uncertainty.
The news comes on top of the development yesterday to restrict the use of the AstraZeneca vaccine to people over 60 years.
The HSE is still assessing the impact of that. Now it has another headache with the news about Johnson & Johnson.
The larger bulk of the Johnson & Johnson doses are due here closer to June.
So it may be that this issue will be resolved soon and not become a major problem for Ireland.
All new drugs and vaccines undergo monitoring when they are made available to the public, after going through trials, and so some of these developments relating to reported side effects are not unusual.
The new Covid-19 vaccines were developed in record speed and it is no surprise they are under close scrutiny by all health authorities.
It makes for anxious times for Ireland, with plans for the vaccination programme to have much bigger numbers of people immunised between now and June.
The European Medicines Agency gave the vaccine conditional approval in mid-March.
It had been already conducting an evaluation of some of the rare blood clot cases in the US. But so far the EMA said no clear link had been established.
Here, the Irish regulator, the Health Products Regulatory Authority, said it is aware of developments and is participating in the Johnson & Johnson EMA safety evaluation.
There is some comfort in the fact that there are several vaccines available for use here and more are expected.
But the AstraZeneca development and now the Johnson & Johnson setback will put more pressure on the HSE to explain how it will readjust the vaccination plans for the crucial months ahead.
Already the AstraZeneca age restriction has resulted in the cancellation of AstraZeneca vaccination clinics for the rest of this week, while the HSE decides how to proceed next with the roll-out plan.
That is except for some people over 60 who will get the AstraZeneca vaccine this week under the new National Immunisation Advisory Committee (NIAC) rules and will be contacted directly by their vaccination centre.