Professor Luke O'Neill says Ireland will be 'awash' with vaccines by April or May.
The Trinity Immunologist says there's room for Ireland to be a 'bit more bold' in terms of the vaccination programme, and it has to be the Government's 'mission one'.
However, he said the next two new vaccines are likely to be approved for use very soon as well - something which should further boost supply.
Vaccination of over 85s is beginning today, although the AstraZeneca vaccine is not being used for that age cohort.
In Ireland, everyone who receives a first dose of the Pfizer or Moderna vaccines receives their second dose around four weeks (28 days) later.
However, similar to the UK, that gap is increased to 12 weeks (84 days) for the AstraZeneca vaccine.
Professor O'Neill told The Pat Kenny Show that evidence is growing that a longer gap may make the AstraZeneca jab even more efficacious than it already is.
He said he understands why people in Ireland are 'envious' of the speed of the vaccine rollout in the UK.
He explained: "There’s evidence that if you leave it for 12 weeks, it’s more efficacious. I’d support the notion of pushing it to 12 weeks for definite.
“One of the challenges we have is a bit too much caution here and there, and in some ways Brussels was a bit cautious as well."
He stressed that people under 70 should not be hesitant in taking the AstraZeneca vaccine, and data suggests it should work in older people very well as well.
He said: "If we have loads of this AstraZeneca vaccine in Ireland, we should begin to use it as widely as possible.
“Remember, the next vaccines are coming soon - Johnson & Johnson and Novavax. We’ll be awash with vaccines by the time we get to April / May time.
“I can see why people are getting frustrated alright - if that frustration continues it won’t be good for us either."
However, he said he wouldn't be too concerned about the current speed here.
He said: "You've got to get enough supply in, and mobilise all the vaccinators - GPs, pharmacists, everyone.
"I would predict in four weeks' time... we'll have a huge amount of vaccination will have happened in this country and in the community, which would be tremendous.
"The Government has to have this as mission one."
'Pan-coronavirus' vaccines
While the focus is currently on vaccinating people against COVID-19, the work that has been undertaken on those vaccines means we could soon see vaccines that are effective against other existing and future coronaviruses as well.
Professor O'Neill explained: “They’re called pan-coronavirus vaccines - meaning all [coronaviruses], really. They’re now being developed, and there’s optimism we may get one.
"That’d be important for new strains that emerge, but secondly [in cases there's] another coronavirus infecting us down the line.
“It was happening with the flu already - they were hoping to get a vaccine for all strains of flu. They almost got there a year ago.
“That notion of a general vaccine against all strains and all coronaviruses isn’t pie in the sky anymore. There are huge amounts of money going into this, and huge research is happening for obvious reasons."
He said the vaccine work currently being undertaken means we could see vaccines against the common cold and any coronavirus.
However, he stressed it's still a 'massive work in progress' and isn't something that's going to happen in the next few months.
