The Johnson and Johnson Covid-19 vaccine has been approved by the European Medicines Agency
It says the single-dose vaccine can be administered for those aged 18 years and over.
The European Commission says it will move quickly to grant approval for use in the EU.
Health Minister Stephen Donnelly's welcomed the move and says Ireland has an advance purchase agreement for 600,000 doses between April and June.
Dr Gerald Barry, an assistant professor of virology at UCD, is also welcoming the news: