The European Commission will secure a contract to buy 160 million doses of the Moderna vaccine tomorrow.
The news was confirmed by President Ursula von der Leyen in a statement this afternoon.
It was announced earlier this month that Moderna's jab may prevent 94.5% of people from getting Covid-19.
Interim data from the US firm suggests its vaccine is highly effective in preventing people getting ill and also works across all age groups, including the elderly.
And speaking after announcing the huge new contract, Ms von der Leyen said: "We are building one of the most comprehensive Covid-19 vaccine portfolios in the world.
"Safe and effective vaccines can help us end the pandemic."
It comes after Taoiseach Micheal Martin gave a major positive update after he revealed plans on how a Covid vaccine will be given to the Irish public is set to be presented in a report to the government in less than three weeks.
The Fianna Fail leader has explained how he is targeting the early part of 2021 for vaccinations here.
Mr Martin said he spoke to Brian McCraith, the chairman of the newly established State vaccine taskforce about the national roll-out of the jab here on Monday morning.
The taskforce met for the first time on Sunday to discuss the logistics of the plan.
Mr Martin said: “They’re working very energetically on this.
“He [McCraith] hopes to have a strategy for the government by the 11th of December, in terms of how we will distribute vaccines."
Meanwhile Chief Medical Officer Dr Tony Holohan has admitted that the vaccine news continues to offer "substantial hope".
Speaking at a press briefing this week he said there was more "encouraging news" in relation to vaccines but cautioned relevant regulatory bodies will still need to investigate how safe and effective they are.
However in more encouraging signs the Chief Medical Officer spoke about the vaccine task force said "there's a lot of good people trying to pull together a national plan" for rolling out the vaccine sparking more hope that delivery won't be too difficult.
