Liam McGuckin, President of school leaders' union NAHT(NI), said: "Following media coverage on Tuesday morning, our members need the Department of Health in Northern Ireland to immediately confirm whether or not workers with symptoms of a respiratory virus, such as sore throat, runny nose or headache must stay off work.

"Knowing that children, young people and adults work closely with each other for long periods of time, with limited ventilation and no realistic opportunities for maintaining physical distance, a zealous interpretation of this advice would have obvious and serious ramifications for the functioning of our schools.

"We must remember that many of our schools continue to face extreme pressures in maintaining safe levels of staffing and so, in order to help us keep our schools functioning, we ask the Department of Health need to clarify this advice very quickly."