The head of AstraZeneca in Ireland says the company's ambition was one of the issues it faced in the early stages of the pandemic.
Dan Wygal was speaking as Ireland is likely to move away from using the AstraZeneca and Johnson & Johnson COVID-19 vaccines.
HSE CEO Paul Reid said earlier this week that countries across the European Union are now set to focus on the mRNA vaccines - Pfizer and Moderna - for the remainder of the vaccination programme and any booster campaigns.
Mr Reid told On The Record: "At the EU-level, the steering board has recommended each country make a decision to suspend the further delivery of Johnson & Johnson and indeed AstraZeneca.
"That's the approach we'll likely be taking."
In his first Irish radio interview Dan Wygal, country president at AstraZeneca Ireland, told The Hard Shoulder he understands people's frustrations.
"I do want to acknowledge some of - I'm sure - the frustrations by the authorities within Ireland, indeed the general public, around the challenges that we had at the onset."
But he says the company has scaled up and optimised its supply chain.
"So what you would have seen over the last several months now is a consistent and reliable supply of the vaccine available across all of Europe.
"And in fact, to this point, we've delivered more than 1.4 million doses here into Ireland".
Asked about the initial issues the company faced, he says this was due to its own ambition.
"There's a few things, and it does relate back to the ambition itself... We're a particularly ambitious organisation, particularly when it comes to science.
"We embarked on this partnership with the University of Oxford, and indeed it was an ambition that normally you would scope out for a period of years - trying to building a supply chain of this magnitude - and we did it in a matter of months.
"So a lot of it frankly was growing pains".
He says the company will continue to watch and analyse real-world data, and is currently working on a variant-specific vaccine.
"We've also begun studying a variant vaccine at AstraZeneca, built on the Beta variant.
"I'm sure everyone, understandably, is very focused on the Delta variant at the moment.
"This Beta variant is one that is of particular interest because it's anti-genetically mutated in a way where it really doesn't look very similar to the previously circulating forms of COVID.
"We have initiated clinical studies around a variant vaccine built off of this Beta variant... part of that would be looking at a booster strategy".
On Ireland's plans to move away from the AstraZeneca vaccine, Mr Wygal says: "I think it again comes down to an understanding of the data and the data which will be forthcoming.
"I think those comments were certainly made in trying to offer some intent around the programme's evolution.
"But again in my discussions, and as the data moves forward, there is huge receptivity to continued sharing of information.
"And in the end I think that's really what it's all about".
He adds he is hopeful AstraZeneca can play a part in this future process.
"I certainly hope so - regardless of whether or not the product is used in a future form or it's current form within Ireland - the mission within AstraZeneca is one that has huge energy and attention to it.
"And that whether it is continued supply here into Europe or in Ireland, again there are so many that remain without protection at a global level.
"So we'll continue to bring the science forward, we'd continue to collaborate with anyone who had interest in the data and the information".
Ireland has also joined the EU in suing AstraZeneca over its failure to meet its coronavirus vaccine delivery targets.
AstraZeneca delivered just one-third of the vaccine it promised in the first quarter of this year.
Under its contract, the Anglo-Swedish company promised to deliver 180 million doses in the second quarter – around 1.8 million of which would have gone to Ireland.
In April, Health Minister Stephen Donnelly said the legal action centred on its "complete failure" to deliver as promised.