A week ago, primary school principal Enda McGorman was confident about schools staying open, but his optimism has given way to fears about their ability to continue if testing and tracing is not speeded up.
As Covid transmission in the community rises rapidly, he says principals can face up to 10 days in the dark about an infection risk that may be spreading through their classrooms and corridors.
"Our system of infection control, hand sanitisation, the pods, the bubbles are all working quite well. You would lick the corridors they are that clean. Last week, I was quite happy and cautiously optimistic that we could keep the whole thing on the road," said McGorman.
However now, he says: "For us to stay open, we need two things to happen.
"We need the community to take responsibility and for parents to drive the virus down by staying at home and following the public health advice.
"We also need a functioning public health response, which includes a track and trace system that is fit for purpose."
McGorman, who is principal of the 430-pupil Mary Mother of Hope senior national school, Blanchardstown, west Dublin, sees a contact tracing system that is struggling to keep up with the Covid spread.
"I am now realising that weight of numbers has an impact on the ability of contact tracers to do their job and we are fearful that without that support, schools cannot remain open.
"We have examples where the delays in contact tracing have been inexcusable and principals have been doing it themselves."
Where a Covid case is confirmed, it is the role of public health teams to arrange for the tracing of close contacts so that they can self-isolate and, if necessary, get tested.
It is in identifying and excluding such risks that allows schools to function as normally as possible and to minimise the possibility of in-school transmission.
However, the tracing doesn't always happen quickly enough and according to McGorman, schools can be waiting for days to hear the outcomes of tests.
It has led to principals sometimes taking matters into their own hands and where, in the interests of speed, "I have done it myself, it has proved very effective and a model of how things should be", he says.
McGorman says he can see the two speeds at which the system works. If he knows of a case and contacts the public health team "I can get it acted on straight away".
If the case goes through the normal process, "by the time the schools are involved it could be five to 10 days later. For close contacts the gold standard is to test on day zero and again on day 17. In some instances, we didn't know until day 10.
"Where a parent tells me, that there is a test coming up, I give my mobile number and, if it's positive, I am straight on to public health, and I short circuit that long process."