The European Medicines Agency (EMA) has given the single dose Johnson & Johnson-developed coronavirus vaccine the green light.
It has recommended granting a conditional marketing authorisation for the drug in people from 18 years of age.
Ireland has an Advance Purchase Agreement for 2.2 million doses of the drug, with 600,000 of those between April and June.
In a decision on Thursday, the agency said: "After a thorough evaluation, EMA's human medicines committee (CHMP) concluded by consensus that the data on the vaccine were robust and met the criteria for efficacy, safety and quality. COVID-19 Vaccine Janssen is the fourth vaccine recommended in the EU for preventing COVID-19."
Health Minister Stephen Donnelly welcomed the move.
Welcome @EMA_News recommendation for COVID-19 vaccine Janssen. Once it gets Commission approval it will become the fourth vaccine authorised for use. Ireland has an advance purchase agreement for 600,000 doses between April and June https://t.co/tkhYwQmHAL
— Stephen Donnelly (@DonnellyStephen) March 11, 2021
EMA's executive director, Irish woman Emer Cooke, said: "With this latest positive opinion, authorities across the European Union will have another option to combat the pandemic and protect the lives and health of their citizens.
"This is the first vaccine which can be used as a single dose".
Results from a clinical trial involving over 44,000 people in the US, South Africa and Latin American countries found that this vaccine has a 67% reduction in the number of symptomatic COVID-19 cases after two weeks.
Half received a single dose of the vaccine and half were given placebo.
The side effects in the study 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 EMA says the safety and effectiveness of the vaccine will continue to be monitored as it is used across the EU.
The European Commission will now fast-track a decision-making process to grant a decision on the use of the drug across the EU.
This is the fourth drug to be approved - following BioNTech/Pfizer, Moderna and AstraZeneca.
The Janssen vaccine only requires a single dose to be effective, unlike all others approved so far, and can also be kept in a standard fridge.
Johnson & Johnson is the parent company of Janssen, both of which have Irish operations.