Would closing Winnipeg schools stop the spread of COVID-19? Expert says the answer is complicated

As calls intensify for online learning amid rising case counts in Winnipeg schools, an epidemiologist from the University of Toronto says we don't yet know enough about school transmission.

As calls for online learning grow, epidemiologist says we don't yet know enough about school transmission

Winnipeg father Martin Zonneveld says he'd prefer to see Winnipeg schools move to remote learning due to the number of COVID-19 cases identified in Manitoba (Walther Bernal/CBC)

Martin Zonneveld, a Winnipeg father of five with four kids in school, would feel safer with his kids at home than in the classroom.

He worries what might happen if one them were to catch COVID-19. 

"I don't need for them to be sitting in the hospital for weeks or months," said Zonneveld. 

The union representing Manitoba teachers announced Thursday it wants the province to shift all public schools in Winnipeg to remote learning starting May 4, in an effort to keep kids and teachers safe as more infectious coronavirus variants of concern continue to spread. 

Nearly two-thirds of schools in Manitoba have had at least one case of COVID-19. The latest data published by the province shows there are 416 cases in Manitoba schools in the last 14 days. Most of the cases are in Winnipeg, with 171 related to variants of concern.

Manitoba Education Minister Cliff Cullen said Thursday the province is watching case counts closely. He said Manitoba health officials maintain schools are safe and most of the transmission is happening outside of them. 

Dr. Colin Furness, an infection control epidemiologist and assistant professor at the University of Toronto, understands why teachers and parents might feel concerned about schools staying open during a third wave of COVID-19 infections. 

"When you've got people all together in a room sharing air and even if there's masks, there's still meal times, that's risky for COVID," said Furness. "With the contagious variants, that risk goes up even more because they're more contagious." 

Furness said it can be hard to determine how much of an impact closing schools has on the spread of the virus. 

"When we close schools … we do it along with a bundle of other measures as well and then it becomes impossible to tease that out." 

When it comes to determining whether schools are safe, Furness said the answer is complicated. 

Colin Furness is an epidemiologist at the University of Toronto, whose research expertise includes information technology and its effect on health behaviour change. (CBC)

One reason for that is schools aren't all built the same way. 

"It depends on humidity and temperature and ventilation and school design and class size," he explained. "There isn't an easy way to certify safety or not and I think that's what drives the concern." 

Another factor is there hasn't been enough data collected about school transmission in Canada, he said. 

"Because we don't understand child transmission of COVID, we definitely don't understand school transmission of COVID," said Furness. "We haven't done any meaningful measurement in Canada."

He said a start would be using rapid testing to help determine how much COVID is in schools. If a large number of cases are identified in a specific place, he said, further testing can then be used to help determine where the transmission is happening.

"You really need to test either randomly, or ideally test universally … get every kid to spit in a cup once so at least you've got a baseline measurement."

 It could also help identify new cases quickly. 

"Even if you don't believe there's any transmission going on in schools, doing testing in schools will help you identify infected families," said Furness. "It actually could work very well for controlling community transmission."

Hard to stay open as case numbers rise

Craig Jenne, an associate professor in the department of microbiology, immunology and infectious diseases at the University of Calgary, said closing schools should be a last resort, but as case numbers rise it can be challenging to keep them open and keep teachers safe. 

"Unless those teachers can be vaccinated … we have to remember that even small numbers of virus in the classroom puts those teachers at risk," said Jenne. "It makes it very difficult to continue school in the traditional fashion."

Craig Jenne is an associate professor of microbiology, immunology and infectious diseases at the University of Calgary. (Jennifer Lee/CBC)

 In Alberta, where new COVID-19 case numbers are surging, he said the province made the decision to close junior high and high schools in certain regions earlier this month. 

He said it's not clear whether kids are getting infected with COVID-19 at school, or somewhere else. But he said in general he doesn't think schools are driving the the high number of new infections in Alberta, though they do suffer when there's a lot of the virus circulating. 

"Really only once the virus was transmitting fairly freely in the community and critically through households is when the cases started ticking up in the schools," he said. "Likewise if we look at the number of cases that we see in the school versus the number of schools that have outbreaks, those are quite different in that it is not uncommon to find kids that test positive in school, but it doesn't always spread through the classroom."

Jenne said it's also important to remember that if there are viral cases in the classroom, everyone has to self-isolate, including the teacher, which means they are no longer able to teach other grades, or other classes.

"What we've seen is a massive shortage of supply teachers and the ability for classrooms to be properly staffed." 

He said when learning is shifted online, teachers can continue to deliver education and they're not pulled out of the school system as frequently. 

With files from Meaghan Ketcheson, Marina von Stackelberg, C. Gowriluk, D. Bernhardt, C. Maclean