Ventilation, testing might be keys to safe school reopening during COVID-19: experts

Getting kids back in the classroom – safely – is a top concern for parents, teachers and health officials, in provinces where children have been repeatedly pulled out of school over successive waves of the COVID-19 pandemic.

But experts warn that if kids go back before appropriate precautions can be put in place, it could just lead to a resurgence of COVID-19 in the community.

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“There are still liabilities in school that need to be dealt with, including class sizes, including ventilation, masking and distancing,” said Dr. Zain Chagla, an infectious disease physician and associate professor at McMaster University. “There could be a roadway to a safe return to school, but it can’t be a safe return to school at pre-pandemic levels. Not yet at least.”

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Masking and ventilation are key, according to a recently released study from the U.S. Centers for Disease Control and Prevention (CDC). The study, which surveyed 169 elementary schools that reopened in Georgia in the fall of 2020, examined the impact of different policies on COVID-19 cases within the schools.

The study found that requiring teachers and staff to wear masks reduced COVID-19 incidence by 37 per cent. Methods of diluting the air – like using fans and opening windows – reduced the incidence by 35 per cent. Additional air filtration reduced the incidence even more.

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Many are welcoming the findings.

“I was quite excited about it, not because I think it provides new information, but because it provides clear evidence of the benefit of ventilation and filtration solutions for classrooms, as well as things like mask-wearing,” said Jeffrey Siegel, an engineering professor at the University of Toronto, who studies indoor air quality.

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Renewed calls for school ventilation upgrades

Renewed calls for school ventilation upgrades – Jan 26, 2021

He said if someone with COVID-19 is in an environment like a classroom, if doors and windows are closed, and air isn’t circulating, the virus particles that they breathe out could build up in the air.

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“When you don’t have that dilution with outdoor air, the air just stays in the space and everything that’s being emitted into the air doesn’t have the benefit of being lost by ventilation,” Siegel said. “So, for example, small respiratory particles, which we know can carry the infectious COVID virus, are going to stay suspended for potentially hours in an indoor environment.”

Potential solutions include opening windows and doors and installing HEPA filters to improve air circulation, he said.

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Some school boards in Canada are working on this. For example, the Vancouver School Board said in a statement that it has increased the run times for ventilated spaces and maximized the amount of outdoor air supplied within the capacity of the heating systems, among other measures.

Not all schools are created equal though, Siegel noted.

“Some classrooms don’t even have windows or don’t have windows that open or they can’t open the windows for safety or security or other reasons,” he said, adding it might be even more important to get HEPA filters into these spaces for further protection.

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Coronavirus: Quebec public health advisor lays out 3 reasons for not recommending air purifiers in schools – Jan 8, 2021

Another layer of safety would be testing, according to Colin Furness, an epidemiologist and assistant professor in the faculty of information at the University of Toronto.

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“There’s a lot of debate about how much transmission occurs in schools. Very few people think there’s no transmission. The question is how much is there?” he said. “We don’t know because we haven’t been doing this sort of testing.”

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Another CDC study examined two high school programs in Utah. In a “Test to Play” program, students were tested for COVID-19 every 14 days before participating in extra-curricular activities like sports. In a second program, schools that identified COVID-19 outbreaks had the option to test everyone in the school, and allow those who tested negative to continue to attend in-person learning.

Both programs were successful in the CDC’s estimation, allowing most in-person sports programs and classrooms to remain open.

“The more testing you do, the more confidence you can have that there is no COVID in a given school,” Furness said. “And when you have that confidence, yes, extracurriculars and other things can come back. But in my estimation, the best defence is regular testing, maybe not ubiquitous, maybe not testing every kid every day, but regular testing, systematic testing and ventilation.”

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COVID-19: Calls in Ontario grow louder for return to in-class learning

COVID-19: Calls in Ontario grow louder for return to in-class learning

Case numbers and vaccination in the broader community are worth paying attention to before making any decisions on opening schools, according to Dr. Anna Banerji, a pediatric infectious disease specialist and associate professor at the University of Toronto.

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“It’s almost June. I’m not sure, especially in areas where there’s a lot of COVID, that it’s worth the risk, especially worth the risk of sending kids back and then having closures again before the end of the year,” she said.

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Having talked to hundreds of families with COVID this year, she said she’s seen a pattern of kids bringing home the infection.

“You see how the kids, they get mild symptoms and then the rest of the family gets sick, or someone ends up in the hospital or someone ends up dying,” she said.

She questions whether opening up now, when some provinces are only just starting to get a handle on COVID-19 cases, is the best decision – even though keeping kids out of school is hard on them and their families.

“You want everyone to be in schools where it’s safe. That’s the better situation. But when the numbers are still high in many places and they’re coming down, can we get them vaccinated first and aim for a very safe and secure start in September?”

–With files from Katherine Aylesworth, Global News

© 2021 Global News, a division of Corus Entertainment Inc.

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