The Thames Valley District School Board (TVDSB) reported four possible cases of COVID-19 on Sunday.
Byron Northview Public School and F.D. Roosevelt Public School both have one case, West Oaks French Immersion Public School now has four, and Southside Public School in Woodstock has two.
No new outbreaks or closures have been declared.
"If you do not receive a letter from Thames Valley indicating the public health unit has identified your child as a close contact, your child is not considered to be at risk," the school board said in a release.
Staff or students who have been identified as a close contact will be notified and are advised to quarantine for 10 days.
The TVDSB are currently tracking 54 cases of COVID-19.
A full list of schools and more information can be found at the TVDSB website.
