Professor Luke O'Neill has said that the Pfizer-BioNTech coronavirus vaccine can now be kept in 'a regular freezer'.
Until now, the drug had to be stored at ultra-low temperatures of between -80°C and -60°C
It comes after the two companies asked the US health regulator to relax requirements for their COVID-19 vaccine to be stored at these temperatures.
They said an approval would allow the drug to be stored in 'pharmaceutical freezers and refrigerators.'
It can also remain stored at these temperatures for up to six months.
The company also said new data has been shared with the US Food and Drug Administration (FDA), "demonstrating the stability of our COVID-19 vaccine" when stored at between -25°C to -15°C for a total of two weeks.
The data has been submitted to the FDA to support a proposed update to its Emergency Use Authorisation (EUA) in the US.
Trinity College Dublin immunologist Professor O'Neill told The Hard Shoulder this is good news for the rollout.
"The Pfizer vaccine is stable in your freezer, which is really good news for storage.
"-70 was the previous temperature, and that's very challenging for all kinds of reasons.
"But they've just submitted to the US administration, the FDA, it's stable at -20".
He said this is the same temperature as "a regular freezer that we all have in our houses".
Prof O'Neill said Pfizer was prompted to test the vaccine on the back of Moderna's success.
"Moderna's vaccine was stable in a freezer, so I guess Pfizer were prompted to test their vaccine - and they've now confirmed it's stable at that temperature.
"So it's good news for storage".
He explained the original temperature, of between -80°C and -60°C, was taken due to the unstable nature of the vaccine.
"These are RNA vaccines, RNA is known to be pretty unstable... so therefore -70, -80 was felt to be the safe bet.
"But of course they hadn't tested -20, whereas Moderna had.
"They were prompted into testing it, and low and behold - they're both RNA vaccines - so it's no surprise really that Pfizer would have the same storage".
'It may get even better'
But he said there is one other difference between Moderna and Pfizer's offerings.
"Moderna keeps in the fridge, then, for 30 days: so you take it out of the freezer [and] stick it in your fridge.
"Pfizer only have a five day test on that, so I bet they'll say it's stable in the fridge for 30 days as well.
"So it may get even better - but it looks as if this makes the whole thing more convenient, obviously".
On the back of the new data Albert Bourla, chairman and CEO of Pfizer, said: "We have been continuously performing stability studies to support the production of the vaccine at commercial scale, with the goal of making the vaccine as accessible as possible for healthcare providers and people across the US and around the world.
"We appreciate our ongoing collaboration with the FDA and CDC as we work to ensure our vaccine can be shipped and stored under increasingly flexible conditions.
"If approved, this new storage option would offer pharmacies and vaccination centres greater flexibility in how they manage their vaccine supply."