BARRIE, ONT. -- Parents are voicing their concerns about school-shared buses after a positive COVID-19 case at one school resulted in implications for another.

"With COVID going on right now, why are they mixing two schools on one bus, three kids to a seat," said mom Cindy Milbury.

Milbury received a letter from the health unit on Monday stating her kids may have been exposed to a student from another school who tested positive for the virus.

Milbury's children attend Boyne River Public School and ride the bus with students from St. Paul's Catholic School in Alliston.

"We can't hardly see our families, and you're putting, I don't know how many kids... 60 kids, on one bus from two different schools," Milbury said.

"It makes no sense whatsoever, and they can't justify it to me at all."

The affected students and a bus driver are now in isolation, with some children having been told to seek testing.

Simcoe County Student Transportation Consortium CEO John Barbato said provincial protocols were followed.

"We do have areas of the County where some schools have to share buses to effectively and efficiently service those students in that community," he said.

Meanwhile, health officials remind students to stay home if they are sick and to wear a mask and keep a safe distance to limit possible exposure on the bus.

"There's certainly difficulties in maintaining cohorts when children are coming from different schools," said Simcoe Muskoka health unit's Dr. John Tuinema. "It's very important to balance the resources we have available in order to make sure that children can go to school as safely as possible."

The student transportation consortium encourages families or parents with concerns over bus routes or health and safety protocols to reach out directly.