Pupils in the Base 11 class at Hollinswood Primary & Nursery in central Telford were told to isolate at home until October 1 after a test returned positive.
A letter home to families said: "On Friday evening we were informed that a member of staff in Base 11... tested positive for Covid-19.
"Parents were contacted directly yesterday with the instruction that their children must self-isolate until October 1.
More Covid-19 coverage:
"Unless the children in that class have symptoms then their brothers and sisters can come into school as usual. At this time no other classes are affected.
"As ever I will keep you informed of any developments and implications across school."
Other schools around Telford & Wrekin that have seen positive cases include Charlton School, Southall School, Captain Webb Primary and Habderdashers' Adams Grammar.