TORONTO -- High school students in Ontario should wear face masks indoors whenever physical distancing rules cannot be followed, but elementary school students should not be expected to follow the same guidelines, according to updated recommendations from experts across the province.

New back-to-school guidance released by Toronto’s SickKids Hospital on Wednesday calls masking in schools a “complex and nuanced” issue and suggests high school students should practise farther physical distancing than younger students because their transmission risk may be higher.

A group of 36 experts including epidemiologists and pediatricians from across Ontario agreed that, based on current science, the use of non-medical masks is recommended for high school students in situations where they could be closer than two metres apart.

Sixty-one per cent of the experts agreed, with 22 per cent recommending mandatory face masks for high schoolers at all times. For middle school students, 64 per cent agreed that masks should be worn when physical distancing can’t be maintained.

“It is important to try to find periods in the day where NMMs (non-medical masks) can be safely removed,” the authors wrote in the guidance.

“However, given that there has been considerable disagreement among the authors around this issue, it will be critical to assess the use of masks on an ongoing basis throughout the school year and adjust accordingly based on the development of further evidence, changes and epidemiology.”

The lack of consensus is a direct result of a lack of evidence on the effectiveness of masking in schools, according to Dr. Jeffrey Pernica, medical director of infectious disease service at McMaster Children's Hospital.

“Being in school is not the same as going to a grocery store or restaurant, and that is why the guidance should not necessarily be the same,” Pernica said during a press conference Wednesday.

“I think we all realize that there are potential benefits to masking in schools, and that it probably will diminish the infectivity of some individuals with COVID. However, there are also a number of potential harms.”

For elementary school students, experts are not recommending masks in school, calling such advice impractical. Younger students may have challenges removing masks on their own and could end up touching their faces more, experts say, thereby putting themselves at greater risk of catching the virus.

“In order to be effective, NMMs would need to be worn correctly, which for many otherwise healthy children and youth will be difficult to do for a full school day; even more significant barriers exist for children and youth with underlying medical, developmental and mental health conditions.”

Asked about the new guidance on masks in schools, Ontario Premier Doug Ford said he would “never argue” with a medical professional, especially those from SickKids.

“So they're the experts when it comes to health and I highly recommend that we follow the health experts as we've been doing from from day one,” he said.

While the province has offered some details of its back-to-school plan, the full picture has yet to be laid out. Ontario Education Minister Stephen Lecce said last week that the government is “finalizing the health protocols” and an announcement is expected Thursday.

DELAYING BAND PRACTICE, FOOTBALL

The new guidance also suggests that schools cancel choir and band practices involving wind instruments for the immediate future and that frequent “nutrition breaks” replace longer lunch breaks to limit unsupervised contact between students.

Schools are advised to delay restarting close-contact sports such as wrestling, rugby, football and indoor team sports such as basketball, and decisions to restart those sports should be made on a case-by-case basis.

Desks in elementary schools should be at least one metre apart, according to the latest guidance, whereas desks in high school classrooms should be at least two metres apart, “given the transmission risk may be higher in this age group.”

Even so, staying two metres apart is still ideal, according to Dr. Charles Hui, chief of infectious diseases, immunology and allergy, at the Children’s Hospital of Eastern Ontario.

“There is discussion in the document on two metres and one metre distancing, but it should be interpreted as a gradation of risk, that two metres is optimal, but the transmission risk at one metre is not significantly different," he said.

"Additionally, it’s difficult to enforce distancing during important developmental play in younger children. And since it is occurring outdoors, the overall risk of transmission in these situations is low.”

Teachers are advised to pay close attention to students’ behaviour for signs of maltreatment, which may have gone undetected during school closures.

CLASS SIZES

While smaller class sizes are recommended, the updated guidance doesn’t specify how large classes should be. While some jurisdictions have opened up classes to groups of 10 to 15 students, the experts say there isn’t enough evidence at this time to set a base class size.

“Decisions should take into account the available classroom space in addition to the number of exposures that would occur should a student or staff test positive,” the experts wrote.

The updated recommendations come more than a month after SickKids released detailed guidance in June, recommending that students practice regular hand hygiene and that some classes be held outdoors when possible. The earlier guidance did not make a distinction between high school and elementary school students.

The Ontario government has previously said class sizes would be capped at 15 students and school attendance would be voluntary and based on parent choice. For students who don’t attend school in person this fall, virtual learning options will be put in place.

Ahead of Ontario’s back-to-school announcement on Thursday, the Ontario Liberals are pushing for Doug Ford’s Progressive Conservatives to invest $3.2 billion to hire thousands more teachers and create 14,000 new classroom spaces in a bid to make classes safer.