Some 70% of people say they are not planning to travel abroad this year.
New ESRI research shows 30% of those who have been vaccinated do have holiday plans.
But less than half of them have actually booked a trip.
Researcher Deirdre Robertson told The Hard Shoulder it is not clear how the resumption of international travel on Monday will influence people's intentions.
"We find that 70% of people say they're not planning to travel in 2021, which is quite a high figure.
"We've broken that down by people who are not vaccinated at all, who've received one dose and those who are fully vaccinated - and it doesn't differ much.
"So across all of those groups it's around 70% say they don't have plans to travel in 2021.
"One difference we find is that people who fully vaccinated, if they plan to travel - so the 30% of them - they're slightly more likely to have booked something.
"But even within that, it's only around half of that group who've actually booked something if they do intend to travel".
But she says these figures could all change after July 19th.
"So much of our behaviour is dictated by, or at least influenced by, what we see people around us doing.
"So if, on the 19th of July, loads of people suddenly book travel I can certainly see that some people will be influenced by that.
"But the other important thing to remember is that what we find is the biggest influence on behaviour throughout this, and since last March, is worry.
"And if people are remaining worried about the virus and about their own personal health, then that might counteract the affect of seeing other people travelling".
This data was collected during the first week of July.
The EU Digital COVID Cert goes live in Ireland from Monday.
However there is still "immense confusion" about what you need to travel abroad, according to travel expert Eoghan Corry.
He earlier told Lunchtime Live: "It's the first time travelling for so many people - it's like our first flight again.
“I think a lot of the complications have probably been a bit overstated. What the Digital COVID Certificate has done is, it has brought together a lot of the scraps of paper into one QR code.
"It is working pretty well right across Europe because it is a couple of Fridays since they introduced this right. I think Romania was a little bit slow in rolling it out but everybody else seems to be doing it quite well."
On her trip to Dublin on Friday, European Commission President Ursula von der Leyen said: "I welcome that Ireland has joined our COVID Certificate. I just today had the opportunity to test it – it works fine."