Pfizer and BioNTech's promising Covid-19 vaccine has moved a big step closer to being used in the US.
An emergency request for authorisation is being made there today.
They say the jab, which is up to 95-percent effective, will be available "within hours" of being approved.
Trinity Professor Luke O’Neill says it's likely to be the middle of next year before there will be a widespread vaccination programme here.
"As soon as we vaccinate even 20% of the people, the dreaded 'R' number begins to go down anyways.
"So we'll see benefits as soon as the vaccination programme begins.
" Once the R number goes to 0.6 or 0.5 that's great, so again, we'll see widespread vaccination by the middle of next year."
The Pfizer vaccine, as well as Moderna's are also both set to be approved in European countries as early as next week.
Approval for two Covid-19 vaccines by The European Medicines Agency to be used in European countries could be granted very soon.
And leading immunologist O'Neill believes the US and EU could co-ordinate their vaccine rollouts.
"They're now co-ordinating with the FDA, so they're talking to each other which is a good development.
"So they can compare notes and come to an approval at the same time, so it can be used all over the world."
