Professor Aoife McLysaght has said the Government should seriously consider the idea of regional lockdowns.
It comes amid a big disparity in levels of community transmission around the country.
Leitrim has had an average of one case a day over the last five days, with a 14-day incidence rate per 100,000 of 34.3.
Offaly, meanwhile, has the highest 14-day incidence rate at 424.6.
Professor McLysaght, professor of genetics at Trinity College Dublin, told The Hard Shoulder people need to see a way out.
"I think it's something that has to be taken very seriously.
"It's clearly not the same picture over the whole country - but it's not just a matter of simply opening up.
"You need to open up and protect the gains we've made.
"For example: if we just said today that Kilkenny's totally open, of course people are going to want to go there.
"They'll come from places like Dublin where there's plenty of COVID, and then you'll be back to square one.
"That's the mistake we made before, that we didn't protect the gains".
'A way out for people'
Prof McLysaght said schools could be the litmus test for re-opening different areas.
"You don't shop around for a school, so... it should be very much the local conditions that decide when the schools can open.
"Some of the schools should have been open before now, and maybe some of them it isn't even safe yet.
"I know people who aren't sending their children to school because it's too dangerous in the area."
And she said businesses should work with others to safeguard the gains that are made.
"There are parts of the country where it's totally safe, where basically it's always been safe, and then there are parts where it's still not safe.
"There has to be a way out of this for people.... and this will be very encouraging, then, for other parts of the country when they see there is something we can do, there is a way out of this.
"But then you do have to protect it - so when you're talking about opening other things, like hospitality, you will have a risk that you're going to be attracting people from other parts of the country that will be bringing cases with them.
"The people who are in business will need to come up with ways, and in consultation with the community, of how do you protect the gains you have - and what would they be willing to do to achieve that?
"When there are no cases in your community, there's nothing to be spread and amplified.
"So we can even predict that it'll be much, much safer in those communities".
