The vaccine is coming, but Northern Ireland will get the Pfizer jab first for around 12,000 top-priority people from as early as next week.
The Republic will have to wait for several more weeks yet.
It follows the decision by the UK's medicines watchdog, the Medicine and Healthcare Products Regulatory Agency (MHRA), to grant the two-dose vaccine emergency approval.
How did the UK manage to be first in the world to approve the vaccine?
The UK withdrew from the EU on January 31 this year so it cut its own deals with the drug companies making potential vaccines.
The MHRA carried out an assessment of the Pfizer vaccine. Ireland and other EU states are waiting for approval from the European Medicines Agency (EMA). Its decision will affect all member states.
As a member of the EU, Ireland has signed up to the Commission-wide system, where it negotiates with drug firms for millions of doses of each vaccine on behalf of all member states.
In the US, the Food and Drug Administration (FDA) is carrying out its assessment.
What has the MHRA found?
It is independent, so it has to be satisfied that the Pfizer vaccine is safe and effective. The company said it is 95pc effective against Covid-19.
The regulator would have had access to a lot of data which has not yet been published.
It must have been satisfied that it had enough evidence to give a decision.
It employs around 1,200 people and its head is Dr June Raine, who has a long track record in the regulation of medicines.
It said yesterday that "no corners have been cut" and its assessment was robust.
When is the European Medicines Agency likely to give its verdict on the vaccine?
It wants to take longer and see more data. It is to convene a meeting by December 29, but it could happen before that.
It will then be decided if there is enough data about the vaccine for it to be approved.
It is also assessing the Moderna vaccine and a decision relating to that jab is due in early January.
How many doses of the Pfizer vaccine is the EU getting?
It has signed up for 300 million doses. Ireland will get around 1pc, approximately three million. As with the UK, the supply will only come over many months.
Is it likely other vaccines will also come on stream?
Yes, there are high hopes for other potential vaccines.
The EU has a deal with Pfizer, Moderna, AstraZeneca, Sanofi, Janssen and CureVac.
The Cabinet here has given approval to enter into an advance purchase agreement for five of the potential vaccines and is expected to give the green light to all six if they are approved.
Was Ireland right to join up with the EU scheme?
It's very much to Ireland's benefit to be part of the deal.
The same price is charged to all member states and Ireland is guaranteed to receive its quota of vaccines over the next year.
Will the MHRA equivalent in Ireland, the HPRA, play a role?
The Health Products Regulatory Authority (HPRA) said Covid-19 vaccines must first be authorised in line with regulations before they can be made available on the market.
For this to happen, the vaccine developers need to submit an application with comprehensive supporting clinical data to the regulatory authorities.
For Covid-19, it is expected the applications for vaccines will be made to the EMA and, if approved, they can be used in all member states.
The EMA relies on scientific expertise from all the national regulatory agencies, including from the HPRA in Ireland.
"The HPRA will be an active participant in the review of Covid-19 vaccine applications," a spokesperson said.
"Our role, working with the EMA, is to carry out a thorough assessment of the supporting data to reach a scientific opinion on whether the vaccine is safe and of suitable quality.
"When the vaccine is in use the HPRA will monitor the safety profile by reviewing all reports of 'suspected adverse events' it receives."