Coronavirus cases have been reported at both a primary school in Enniskillen and a Belfast supermarket.
Parents at Florence Court Primary School received a letter this week confirming that a member of the school community had tested positive.
A member of the public also raised concerns after claiming a staff member at Marks & Spencer on the Lisburn Road had contracted the virus on Wednesday, causing "huge concerns" among colleagues.
The letter to parents said that Florence Court's nursery bubble will be closed until Tuesday morning to allow for a deep clean. Yesterday the P1, 2, 3 and 6 bubbles remained open to pupils as planned.
"We do appreciate the concerns of parents, pupils and the wider school community and wish to reassure you that every precaution has been taken," the letter said.
Ulster Unionist MLA Rosemary Barton said she understood the concerns of parents, but praised the school for acting swiftly to put their Covid protection plan in place.
"I understand that the bubble which the person was within at the school has been advised to remain at home until further notice, but as appropriate protocols are in place the majority of pupils can continue to attend school."
An M&S spokesperson said: "The health and wellbeing of our colleagues and customers always comes first and we have enhanced cleaning procedures and measures in place across all M&S stores to help ensure social distancing.
"We have been in touch with the Council and we are happy that the Lisburn Road M&S store is following all proper procedures and is fully in line with Government guidance."
The Public Health Agency said it does not comment on individual cases.