More than 30,000 people tested positive for Covid-19 in Northern Ireland over the New Year period, according to figures released by the North's Department of Health on Tuesday.
A total of 30,423 new positive cases of the virus were confirmed between midnight on December 30th and midnight on January 3rd.
The department also reported 15 deaths with Covid-19 during the same period.
Dr Connor Bamford, a virologist at Queen's University, Belfast, told the BBC that case numbers in Northern Ireland were "going to get worse before it gets better" and while there had been a "slight increase" in the numbers of hospitalisations and deaths he did not expect it would be as severe as previous waves of the virus.
On Tuesday, 348 patients with Covid-19 were receiving hospital treatment in the North with 31 in intensive care.
Meanwhile, the return of the majority of pupils to school in Northern Ireland on Tuesday following the Christmas holidays prompted a warning from a teaching union that this could lead to a further rise in case numbers and raised concerns over contact tracing, staff shortages and the difficulty in finding substitute teachers.
Graham Gault from the National Association of Head Teachers said experienced showed "that children spread this virus from child to child and we would expect that to be even more noticeable with the arrival of the Omicron variant".
He asked the Minister for Health, Michelle McIlveen, to “make it very clear to our parents that school leaders want our children to be in school but they can’t perform miracles, and if staffing levels necessitate a temporary closure or a move to remote learning for some children, for a class or a year group or a whole school, then the communities should be understanding of that.”
Speaking on the BBC’s Good Morning Ulster programme on Tuesday the Minister said the “priority” was to keep children in school and there had “not been any change to the guidance as regards to Covid, because this very much comes as a recommendation from the Department of Health [and] at present we haven’t received anything different.”
She said schools could use remote learning in a number of scenarios, “particularly where they are experiencing staff shortages”. – Additional reporting: PA.