An adviser to the World Health Organisation has said Ireland should allow Covid-19 to spread in a "controlled" way among people under 60.
Johan Giesecke, Sweden's former chief epidemiologist and a member of the WHO's strategic and technical advisory group for infectious hazards, made the comments at the Oireachtas coronavirus committee on Wednesday morning.
Several medical experts are appearing before the committee, which is examining options for eliminating community transmission of Covid-19.
Mr Giesecke said the Government should allow a controlled spread of the virus among people under 60 and concentrate on protecting the old and frail, with frequent tests of staff and residents in care homes.
Following Mr Giesecke's comments, Taoiseach Micheál Martin said he does not support a herd immunity approach to dealing with the virus.
“I don’t believe in the herd immunity approach... and those who advocated it early on in my view, didn’t fully realise the impact of this virus on people and on people’s health," he said.
"Even if you survive it can be very damaging it seems to lungs and to people’s health over the medium term – some people, not all people.”
Mr Giesecke also said the Government should not build its Covid strategy around a possible vaccine.
He said there could be a long wait for immunisation and it may not be effective for those who need it most.
Addressing the committee on Wednesday morning, Dr Giesecke has said his country’s “soft lockdown” worked because the country trusted its people.
Dr Giesecke said “people are not stupid” and will respond if told how to protect themselves.
He said schools must remain open and he pointed out that there was no difference between infections among schoolchildren in Sweden, where schools were kept open, and in neighbouring Finland which closed its schools.
Dr Giesecke said Covid-19 constituted a threat to democracy in many countries with some politicians acquiring extra powers that they might not relinquish.
Dr Martin Daly, a former president of the Irish Medical Organisation, disagreed with the approach.
Speaking to Newstalk, he said: "In my view, it is a social experiment as it runs the risk of spreading to our vulnerable groups. Because even with the best will in the world, it will take a certain degree of discipline to protect our vulnerable groups.
"I still think we should follow the current NPHET [National Public Health Emergency Team] advice," he said.
Later on Wednesday, the president of the Irish Society of Clinical Microbiology, Kirsten Schaffer, will tell the committee that Ireland should also stop aiming for Covid-free status or even for levels as low as in July at the end of lockdown.
The “economic and social impact would be devastating”, she is expected to say.
The chair of the Oireachtas Covid-19 Committee, Independent TD Michael McNamara said one of the questions to be answered at the meeting is the measure of success of restrictions and lockdowns.
Mr McNamara told RTÉ radio’s Morning Ireland the key question was what had been achieved by lockdown and what was the measure of success.
The recent restrictions in Offaly and Kildare appeared to have temporarily suppressed the virus, but numbers were rising again. Was there something else that needed to be done, he asked.
Mr Giesecke's advice to allow a controlled spread among younger people raised the question if the vulnerable should be shielded while the remainder of the population was allowed to move more freely, said Mr McNamara.
Many people over the age of 70 would not be prepared to do that, he said, so was it down to a matter of personal choice.
This comes after Dr Ronan Glynn, the acting chief medical officer, warned that Covid-19 is spreading "disproportionately" among younger people.
The latest figures from the Health Protection Surveillance Centre show 40 per cent of cases in the last two months have been in people aged between 15 and 34.
Another 334 cases of the virus were reported across the country on Tuesday.
NPHET will consider whether to recommend further restrictions at a meeting on Thursday. Up to eight counties are in danger of moving to Level 3 restrictions, the same level in force in Dublin.