Dozens of staff are out of work due to Covid-19.
Theresa O'Brien says the Intensive Care Unit at the hospital is full and is calling for people to stay home and not mix with other households.
Over 100 nurses are not available to work at the hospital due to Covid-19, according to the Irish Nurses and Midwives Organisation, leading to fears of a staffing crisis.
The boss of the HSE says daily case numbers could rise to a record 7,000 in the coming days and says elective procedures and non urgent appointments will be cancelled.
Speaking on the Neil Prendeville Show on Cork's RedFM, clinical nurse manager at CUH Theresa O'Brien says many frontline workers feared the easing of restrictions in December would have an impact on the number of people contracting Covid-19:
