Two more cases of COVID-19 have been linked to Sarnia's Northern Collegiate Institute & Vocational School.
The Lambton-Kent District School Board's COVID-19 advisory page Wednesday afternoon showed two confirmed student cases, but the school remained open.
In a letter to parents dated December 2, Lambton Public Health said it's working closely with the school community and is contacting any individuals who may have been in potential contact with the virus.
The health unit said If you have not been contacted, you have not been in close contact with the confirmed case.
Parents are being asked to continue to monitor their children for symptoms of COVID-19 and complete the daily school screening assessment tool.
Those experiencing symptoms are asked to remain at home and contact their healthcare provider.
Two cases were previously reported at the Sarnia high school in October, but have since been resolved.