The vaccine has been described as a "game-changer".
The European Medicines Agency has given approval for Johnson & Johnson's Covid-19 vaccine to be used in the European Union.
The Covid jab is the first approved for use in the EU which only requires one injection, as opposed to AstraZeneca, Pfizer and Moderna's two.
It also does not need ultra-cold storage and can be stored at fridge temperature for at least three months.
Its these qualities which have led to Taoiseach Micheál Martin calling the vaccine a potential "game-changer" for Ireland.
The EMA has recommended granting a conditional marketing authorisation for the jab to be used in people from 18 years of age.
They concluded by consensus that the data on the vaccine was robust and met the criteria for efficacy, safety and quality.
Results from a clinical trial involving people in the United States, South Africa and Latin American countries found the jab was effective at preventing the virus in people 18 and over, with the vaccine having 67% efficacy.
Side effects were usually mild or moderate and cleared within a couple of days after vaccination.
The most common ones were pain at the injection site, headache, tiredness, muscle pain and nausea.
The safety and effectiveness of the vaccine will continue to be monitored as it is used across the EU.
The US Food and Drug Administration has already given the jab emergency approval.
Ireland is expecting to receive 600,000 doses of the new vaccine during this year's second quarter, with hopes it will boost the country's rollout which has faced criticism over delays.
Two weeks ago, the Taoiseach said that Ireland would administer 1.25 million jabs by the end of March, but since then the HSE has revealed that goal will be missed by hundreds of thousands.
Speaking on
RTE's News at One on Wednesday, Tánaiste Leo Varadkar admitted these delays were "very frustrating" but were out of the government's control.
He said: "We try to level with people by giving them the most up to date information but the downside of that is that the information does change.
"We still think about 1.1 [million] doses will have arrived in the country by 31 March.
"But some of them may arrive on the 31 March so it's going to take three or four days before they actually get into people's arms."
As of last Sunday (7 March), there have been 525,768 doses of Covid-19 vaccine administered in Ireland.
375,521 people have received their first dose and 150,247 people have received their second dose.
