Coronavirus will “come back with a vengeance” if lockdown measures are eased too quickly, Wales’ chief scientific adviser for health warned.
Dr Rob Orford said a “very careful, cautious approach” was required.
He said communicating the plan effectively to the public would be key and that children could be among the first to see changes.
Surveillance measures would also need to be in place to track and trace ongoing infections, Dr Orford added.
“The risk of a second and third (Covid-19) wave are ever-present,” he said.
“We don’t know the prevalence of the infection – we don’t know if people have a lower risk if they’ve been exposed and have become ill from coronavirus.
“So there are some key questions that we need to answer as we edge our way forward.”
He said if we “throw the doors wide open”, the virus could “come back with a vengeance”.
Asked if it was premature to talk of easing restrictions before a surveillance strategy had been published, Dr Orford said work on both elements was happening “hand in hand”.
“A complex set of calculations and policy decisions need to go on,” he said.
“We’re working very closely at a UK level and looking overseas at international efforts so we can learn from others.”
Testing would become “more important”, he said, but was “not a panacea”.
Deployment of a smartphone app to track and trace people with symptoms – currently being trialled on the Isle of Wight – is also being considered alongside other “technological innovations”.
On whether schools and nurseries should be among the first parts of society to reopen, Dr Orford said there was an increasing amount of evidence suggesting the virus had less impact on younger age groups.
He said: “You can probably conclude from that they would be the best group to look at first.”
However, he said there was less certainty about the role of children in transmission of the disease.
“We need to carefully look at what other countries are doing to make sure we not only reduce the direct impact of coronavirus on children but also think about the indirect harms closing schools will have on their future as well,” he added.
‘Long way off beating it’
Meanwhile, Professor Judith Hall, a Cardiff-based consultant anaesthetist, said an easing of lockdown restrictions should be done “cautiously”.
Prof Hall, who has an OBE for her services to medicine and was once named Welsh Woman of the Year, has been on the front line fighting Covid-19.
“This is about protecting lives,” she said.
“It’s our mothers, fathers and ourselves that could be put it risk. We need to extraordinarily cautious because we really do not yet know enough about this virus – and we’re a long way off beating it.
“Just because the infection rate and the number of patients being admitted to intensive care are starting to come down, I think we can become far too complacent.”
Prof Hall said she was hopeful that when the lockdown starts to unwind, people will act “very sensibly” and not “rush out to get-togethers and parties, because that’s the problem”.
She has seen for herself the impact on her colleagues as they treat the sickest Covid-19 patients at the University Hospital of Wales in Cardiff.
Most of the 184 people who have died in the Cardiff and Vale University Health Board Trust area with Covid-19 died in hospital.
“The psychological toll on staff has been tremendous,” said Prof Hall.
“People keep saying a second peak is inevitable but oh my goodness, please let’s make that second peak as small as possible.”
While the lockdown in Wales will be reviewed this week, First Minister Mark Drakeford has said he was in “broad agreement” with a draft UK government strategy for England, seen by the BBC.
He has also called for the four UK nations to ease restrictions according to a “common timetable”.
However, Prof Hall said: “I don’t think we should act at the same rate as England.
“We’ve a different population, we’re older and more rural in general, so I think we should make our own decisions.”