Two elderly people 'cocooning' at home are feared to have caught Covid-19 from visits by healthcare support workers.
The cases - in the south and west, which are totally unrelated - are currently under investigation by health chiefs.
However, in one case the person reported no contact with family, friends or neighbours - and only had visits to their home by healthcare support workers.
A contact tracing centre source indicated that the person was adamant their only home contact was with healthcare support officials.
In the second case, the person was living in self-imposed isolation with their spouse.
Only two family members had visited the house to drop off food and necessary supplies.
Both had kept their distance and did not enter the property.
Two healthcare support workers also visited the house on a daily basis to help the elderly couple with their washing and cleaning.
The elderly person later complained of feeling unwell and was transferred to hospital.
Tests later confirmed that the pensioner had, as feared, caught Covid-19.
After treatment in an intensive care unit, the pensioner rallied and is recovering in a special step-down facility.
The pensioner has a serious underlying health condition.
However, the person's two children are understood to have shown no symptoms of the virus and are currently awaiting the result of Covid-19 tests.
"We were told that the virus could only really have come from the home carers or from ourselves," a daughter of the pensioner said.
"My parents have not left their house except to go into their garden since this whole virus scare started.
"Myself and my brother were very careful to socially distance from our parents.
"We called to the house each day and dropped messages outside the front door. But we did not go in. So we really believe that it could only have come from the carers."
One of the pensioner's children is an asthmatic and had been carefully isolating themselves.
Further, both are adamant they maintained full social distancing when calling to the house and did not have any direct contact with their elderly parents.
The woman said she had not been informed of the Covid-19 test results conducted on the carers involved.
The cases are both under review amid indications the virus may unwittingly have been passed on by healthcare support workers despite the staff wearing both protective gloves and masks.
The HSE said it could not comment on individual cases saying maintaining confidentiality was an "ethical" and "legal" requirement.
It said the spread of Covid-19 has posed "significant challenges" to home support services and it has had to reassess the operation of these services in light of social-distancing guidance "to ensure that the assessed needs of those clients with the highest priority are met".
Meanwhile, Irish health chiefs have admitted that the latest profile on Covid-19 by virologists indicated that between 30pc and 50pc of the population may contract the virus without displaying any discernible symptoms.
Early reports from China had indicated that such asymptomatic cases represented only 1pc to 2pc of all infections.