B.C. students returned to school today (September 10), and parents, teachers, school administrators, and politicians now anxiously await news of potential COVID-19 outbreaks.

But two Simon Fraser University mathematics professors have written that "a large number of high schools" in the Fraser Health and Vancouver Coastal Health regions are at "serious risk" of outbreaks.

And a Vancouver software engineer and mathematician has modelled scenarios that show hundreds of students contracting coronavirus.

One of the SFU profs says that closing bars, among other things, would help pave the way for a more positive eventual outcome.

Caroline Colijn said that after Phase 3 of B.C.'s pandemic restart plan allowed bars, clubs, and restaurants to reopen, COVID-19 case numbers started climbing until, after mid-July, they started "doubling every 15 to 18 days".

"Cases in B.C. have been following a very predictable trend, unfortunately," Colijn, a Canada 150 Research Chair, told the Georgia Straight by phone.

Colijn and SFU math professor Paul Tupper published an article in Medium on August 14 detailing some of their COVID-19 modelling for B.C. that they had researched for a paper they posted on a preprint server while it is under review for future publication.

In the article, they looked at what B.C. could expect when schools reopened in terms of outbreaks, with possible outcomes based on a single infected person in a medium- to large-size high school.

"The chance that a school with 1500 students has at least one entering who is infectious is 20–30%. That’s a large number of high schools in the VCH and FH region that are at serious risk of an outbreak, right away," they wrote.

They went on to predict that "a single asymptomatic student could infect between 10 and 25 other students in a single week. Then, before they know they are ill, those new cases could infect many other students, family members, teachers and other contacts. This could lead to outbreaks in the dozens to hundreds."

Colijn said that part of the difficulty in predicting potential high-school COVID-19 outbreaks is the infected students themselves: "We just don't know, exactly, how many people in their age group will have symptoms and how many will know they're ill enough to stay home," she said. "It's the first day of school, and everyone will want to go."

The pair's low-end prediction for COVID-19 prevalence in B.C. by September 11, 1,500 cases, might have been right on the money. The actual number of active cases, released by provincial health officer Dr. Bonnie Henry on September 10, is 1,412, a record high, with one day's totals to go.

Colijn and Tupper—along with SFU research assistant Himani Boury and master's student Madi Yerlanov—authored a preprint paper (under review) published July 10 in the journal medRxiv that examined different scenarios wherein a single infected individual presented under different conditions and which barriers to prevent coronavirus transmission would be most effective.

In the face of the July rise in B.C. COVID-19 cases, Colijn said, the province "didn't take any more drastic action", although she said the recent (September 8) closing of nightclubs and restrictions on the number of hours that bars can serve alcohol will probably help.

"It's better to be outdoors," Colijn said. "Parks, not bars...They've said it in California; they've said it Washington [state]," she noted, referencing those states' reclosing of bars in July after spikes in COVID-19 cases. At a July 23 news conference announcing the closures, Washington governor Jay Inslee said, in response to a question as to why bars faced more drastic pandemic measures than restaurants, "There’s a social behavior associated with alcohol that’s different than carbohydrates.”

"People drink in bars," Colijn said, "and they lose inhibitions when they drink...We think that one of the best ways to prevent school outbreaks is to get control of community transmission."

But Colijn noted that bars aren't the only source of community transmission that could make its way to students attending reopened schools. "I don't want to pick on bars," she said. "In my opinion, we need to make sure there is no transmission in the broader community."

She said that during the pandemic, people should be striving "to stay out of close indoor contact as long as possible, whether that's bars, patios, or whatever".

In a cautionary passage in their Medium article, Tupper and Colijn wrote: "Face masks and social distancing will make the [school COVID-19] numbers lower, as will students staying home if they feel sick (for those who get symptoms). But two lessons remain despite the uncertainty: the number of new infections will not be small, and bubble sizes of 120 (for high schools) and 60 (for elementary schools) will not make much of a dent."

Meanwhile, a Vancouver-based mathematician has come to much the same conclusions as the two SFU profs regarding the probability of COVID-19 outbreaks in Vancouver schools.

Jens von Bergmann, a software engineer and a former university instructor who founded MountainMath, a data-analysis company, is also known for creating interactive graphics that illustrate Vancouver housing trends.

In a September 8 article on his Mountain Doodles website, using modelling adapted from a University of Washington model, four simulated scenarios show anywhere from 153 to 428 COVID-19 cases in schools during a 60-day period.

At the conclusion of his article, Von Bergmann wrote: 

"The cases the model produces are at the upper end of what one might expect to see. What it does show is how implementation details on the test, trace and isolate (TTI) response matter to moderate the outbreak size.

"The specific implementation of our TTI protocol matters in controlling school outbreaks, and it can be the difference between schools being infection accelerators and places that experience occasional exposures but don’t add significant transmissions."