A St John Primary school student in the same class bubble as the child who tested positive for coronavirus earlier this week has also now tested positive.
All children in that bubble went into self-isolation after the first student was diagnosed. The news of that case was sent to the media on Wednesday night.
Therefore, the affected students haven't been in school since then.
The government says it is not commenting further to protect the identity of this child and to respect the family's privacy.
The school was disinfected after the first case was discovered and it remains open to other students and staff.
There are now 82 known active cases of coronavirus in Jersey.