NHS guidelines: is my child too ill for school?
Coughs and colds
It's fine to send your child to school with a slight cough or common cold symptoms, such as a runny nose, sore throat or headache, as long as they're otherwise well and do not have a high temperature.
If they have a high temperature, keep them off school until the temperature has gone.
Encourage your child to throw away any used tissues and to wash their hands regularly.
Please click on this link for more advice:
Is my child too ill for school? - NHS