A member of staff at Hautlieu has tested positive for coronavirus.
Contact tracing is underway to determine close contacts.
Channel 103 understands that the confirmed case is related to Year 10 at the school, who will now be told of the next steps.
It's understood that students in that year group, along with some members of staff, have been told to stay at home tomorrow (Friday 13 November) as a precaution so testing can be completed.
"The areas have been deep cleaned and the school will remain open following advice from Environmental and Public Health.
"We are committed to supporting our students who have been impacted by the pandemic. Students who have to be at home due to Public Health guidelines will continue to receive school work online so that they can continue with their education.
"To protect the identity of the students and respect the family’s privacy, we will not be commenting further."
Two students at Hautlieu were confirmed to have tested positive for Covid-19 last week.
Haut du Mont trial: Island Energy 'placed health and safety at risk'
Deportation recommended after sex-demanding attacker jailed
Teenage boy arrested on suspicion of sexual touching at Millbrook Park
Eyes up! It's Air Display day...
Haut Du Mont Trial: 'It could explode', jury hears 999 calls
Haut Du Mont Trial: Worker checking gas valves spent almost 'entire' time on his phone
Red Arrows still expected for Jersey Air Show
Haut Du Mont Trial: Gas works were 'sloppy, unsafe, and cut corners', allege prosecutors
