Frontline health staff and nursing home residents are expected to be among the first to get the Covid-19 vaccine if it is approved for use here from early January.
It is hoped the first consignment will include 300,000 doses of the Pfizer-BioNTech vaccine, enough for 150,000 high-priority people.
But who is likely to be advised not to take the jab initially?
And if you already had the virus do you need to be immunised?
The National Immunisation Advisory Committee in the Republic will be the group that decides who should and should not get the Covid-19 vaccine initially.
However, it is likely their guidelines will strongly mirror those of experts in the UK where the vaccine is being rolled out this week.
UK experts have recommended that expectant mothers should not be offered it for now.
Although they are in a younger age group and would not be eligible for the vaccine until well into next year, the advice is relevant to pregnant healthcare workers, who will be among the first in line for the vaccine.
The UK's Joint Committee on Vaccination and Immunisation said so far, there is a lack of evidence of the effect of the vaccine, but said more research will be carried out.
Women who are planning to get pregnant within three months will also be excluded.
It said that data on vaccine impact on transmission, along with data on vaccine safety and effectiveness, will potentially allow for consideration of vaccination across the rest of the population.
As trials on children and pregnant women are completed, a better understanding will be gained.
Once a woman gives birth, she can be vaccinated. It will be important for women who are deemed at high risk of being exposed to the virus or getting very ill as a result of Covid-19.
CHILDREN UNDER 16
The committee also advised against immunisation in the under-16s because there is limited data on vaccination in adolescents, with no data on younger children at this point.
It suggests that only children at very high risk of exposure to the virus and serious outcomes, such as older children with neuro-disabilities, should be offered the vaccine.
The guidance allows for breastfeeding mothers to get the vaccine.
WHAT ABOUT PEOPLE WHO HAVE ALREADY HAD THE VIRUS?
The vaccine will be offered to people who have recovered from the virus.
There have been a number of cases reported of people being reinfected, so there are no guarantees that recovery itself provides immunity to the virus.
A report by Hiqa, the health watchdog here, said immunity lasts for at least two to six months.
However, people who had the virus must continue to follow safety measures such as physical distancing and wearing a face mask.
Some experts believe that a vaccine could even work better on people who had the virus because they may still have some residual immunity left which is enhanced by the vaccine.
Some of the volunteers in the Pfizer-BioNTech trials had the virus but were unaware of it.
Some vegetarians or vegans may be loath to take the vaccine if there are any animal ingredients in them.
Other, long-established vaccines, such as the nasal flu vaccine currently given here to children, contain pork gelatine.
Some can have hen's eggs, or cells from chick embryos.
It is still unclear what the full ingredients of the vaccines are, but experts believe they will be vegetarian - or vegan - friendly.
Ireland will be able to learn how the rollout of the vaccine works in the UK, including the North, before the expected first consignment arrives later this month or in January.
There is already good news from the UK's medicines regulator, the MRHA, about the possibility of bringing the vaccine to nursing homes, which could potentially be copied here.
It was thought this would present difficulties because of the way the vaccine in packaged. But it has now confirmed it may be possible shortly.
The packs can be broken down into smaller consignments and distributed to nursing homes in about two weeks.
The vaccine doses must be repacked for transport to nursing homes in refrigerated cold rooms at between 2C and 8C and transferred into carriers that maintain the same temperature.
When these vials of vaccine are thawed, there is a window of just 12 hours to pack them and transport them to the nursing homes.
The MRHA said there "should be no doubt" about the safety of the vaccine.
The US regulator, the FDA, will meet on Thursday to decide if it will grant approval.
If so, the way for the vaccine should be cleared on Friday for the US.
That leaves Europe and countries like Ireland waiting for the green light from the European Medicines Agency which said it will meet before the end of the month.
Once it is approved, the wheels can be put in motion to transport it to Ireland and other EU countries.