WINNIPEG -- As children across Manitoba returned to school this week, many parents are concerned about COVID-19 cases in schools.

This week, a Grade 7 student at Churchill High School in Winnipeg tested positive for COVID-19. Manitoba health officials have said cases are expected at schools during the pandemic but said the risk of exposure from the case this week is low.

Dr. Jason Kindrachuk, an emerging virus expert, spoke with CTV Morning Live on September 11 about the topic and transmission of COVID-19 among children.

He said researchers currently do not understand all the nuances of COVID-19 in children.

"We're in a little bit of a grey area when it comes to transmission," he said. "Just because you have the virus there doesn't mean you can automatically transmit it to other people. That's where we really don't understand this, even though we're doing all of this research in a lab, that doesn't really provide us with the direct information on how do kids transmit this virus to others."

Kindrachuk was also asked about the latest information about asymptomatic transmission, where a person not showing symptoms of COVID-19 could potentially infect someone with it.

"We know that, much like influenza, people can transmit in that period up until that point they develop symptoms," he said. "The problem is, we think it's a little bit longer than what we see with influenza, and that makes it more difficult because we have to try and figure out how best to manage those people who don't know they're infected."

"This is where the masking principle becomes so important because whether it's one day prior to developing symptoms, or three days or potentially five days prior to developing symptoms, you're not going to know if you're infected. So using a mask is at the very least going to stop you, or at least limit somewhat, your ability to transmit that virus."

Masks are mandatory for students in Grades 4 and up in Manitoba schools.