Montreal schools now driving force of transmission
Poorly ventilated and crowded schools reporting infectious clusters
MONTREAL - It’s Montreal schools that are now driving the transmission of the coronavirus in the community, say two experts who have examined the latest public health data showing rising cases and outbreaks among students.
Since the start of the academic year, authorities have maintained that COVID-19 cases in schools merely reflect what’s going on in the community and are not the driving force of transmission.
However, the Montreal Gazette has obtained data from the public health department and educational system revealing that the city’s mostly poorly ventilated and crowded schools are now reporting more infectious clusters than in the workplace and health-care institutions combined.
This shift in transmission has implications for public health policy, as federal officials this week acknowledged that the coronavirus can spread easily through the air in lingering aerosols in addition to respiratory droplets, yet most Montreal schools without modern ventilation have no plans to install portable air purifiers in their classrooms.
“Schools were the driver to start the second wave in Quebec, although the government did not recognize it,” Dr. Karl Weiss, president of the Association des médecins microbiologistes-infectiologues du Québec, said in an interview Thursday.
“The number of cases started to go up 14 days after the French-language schools opened and 14 days after the English ones opened in Montreal. Schools are certainly a driver.
“It’s true for any respiratory virus,” Weiss added. “It’s true for the flu. It starts in schools, kids will bring the virus back home and infect the parents, and parents will get sick. Eventually the parents will infect their coworkers and it will spread to the community.”
Weiss suggested that arguably the main reason COVID-19 cases in Montreal have not sloped downward from a plateau of more than 200 a day in the last few weeks is that transmission is active in schools.
“Where are the cases coming from?” Weiss asked. “From schools and from teenagers hugging each other. I was walking towards my house and I saw a group of 20 to 30 teenagers without masks talking to each other because they have nowhere else to go. They can’t go do sports.”
There are currently 96 COVID-19 clusters in Montreal schools, up from 93 on Friday. By comparison, there are 70 active outbreaks in the workplace and 25 in healthcare institutions, according to the public health department.
What’s more, the age group in Montreal that has been posting the highest number of cases in the past 14 days are 10-to-19-yearolds, most of whom attend high school. Since the start of the school year, this demographic has observed an increase of nearly 160 per cent in the number of COVID-19 infections, by far the greatest of any age group.
Despite the data on rising cases and outbreaks in schools, a spokesperson for the public health department denied that the school environment is driving the spread of the coronavirus in Montreal.
“The schools are not acting like engines of outbreaks,” Jean Nicolas Aubé said. “In fact, schools are a reflection of community transmission. The cases in the school milieu are relatively stable, and in a majority of instances, the source of the transmission comes from parents.”
But Dr. Michael D. Levy, a Montreal public health consultant, said there’s an obvious discrepancy between what the epidemiological data show about Montreal schools and Aubé’s assertion.
“The percentage of cases in the schools is much higher than in the general population,” Levy said. “Why is that? I don’t know how (public health) calculates this because they’re very cagey about sharing the data.
“I don’t know how they can tell most of the cases are coming from the home,” Levy added. “When they opened the schools in the fall, there was an immediate surge in cases. I think it came from the schools because it wasn’t that bad during the summer even though bars, restaurants and gyms were open.”
On Thursday afternoon, Quebec’s chief public health officer, Dr. Horacio Arruda, attributed most outbreaks across the province to the workplace, but he did not allude specifically to the Montreal context.
Arruda suggested that although schools have shuttered classes because of COVID-19 exposure, “there is not that much transmission as such.”
The Quebec Education Ministry counted a total of 2,455 active cases among students and school staff across the province Thursday, up by 45 from the day before. The number of schools with at least one case inched up by a dozen to 877, and 851 classes are shuttered.
Leon Wang, an associate professor of building, civil and environmental engineering at Concordia University, noted that in general, poorly ventilated and crowded spaces — which are the conditions in many Montreal classrooms — pose a higher risk for viral transmission.
Wang urged schools without proper ventilation to install portable air purifiers with HEPA filters in classrooms — initiatives that have already been undertaken in Toronto and Vancouver. In September, Quebec announced $20 million for the maintenance of the existing ventilation in the province’s 3,000 schools, but no new funds for air purifiers.