Please follow the advice from Public Health England and keep pupils at home if they have coronavirus symptoms.  These are defined as:

You do not need to contact 111 to tell them you’re staying at home. If you have symptoms, stay at home for 7 days if you live with other people, they should stay at home for 14 days from the day the first person got symptoms. If you live with someone who is 70 or over, has a long-term condition, is pregnant or has a weakened immune system, try to find somewhere else for them to stay for 14 days.