Thread by @Aaron_Derfel

1) In less than two weeks, the number of Montreal schools affected by the #pandemic — but not necessarily declaring outbreaks — has nearly quadrupled. In this thread, I will try to explain what may be going on within the student population in the city.

2) Please compare the two maps below, courtesy of covidecolesquebec.org, the first dated Sept. 6 and the second today, Sept. 18. In the first map, Montreal counted two dozen schools where at least one student or employee tested positive. By Friday, that figure jumped to 93.

3) One of those schools, Herzliah, was forced Thursday to close for two weeks after a #COVID19 outbreak infected at least 15 students and a teacher. Six other schools have confirmed outbreaks less than three weeks into the academic year, according to the public health department.

4) Across the province, a total of 507 students and school employees screened positive for the #coronavirus as of Thursday, up from 453 the day before. The number of classes that have been shuttered temporarily rose to 189 from 173. Please see the chart below.

5) Since the start of the school year in Montreal, the sharpest percentage increases in positive tests results are among high school and elementary students, among all age groups. The increases have been 12.33% in the 10-to-19 age group and 11.86% in the 5-to-9 demographic.

6) Dr. Mylène Drouin, chief of the public health department, emphasized this week that the source of much of the positive #coronavirus tests in schools is the community at large, not schools per se. But as the school year wears on, that distinction will no doubt become blurred.

7) The spike in cases among students may result partly from Quebec conducting record-high testing. But Australian epidemiologist Zoë Hyde has warned “large clusters in school settings have been reported (elsewhere), with implications for the control of community transmission.”

8) As I’ve written before, #COVID19 cases in schools aren't occurring in a vacuum. On Friday, Montreal’s seven-day average rose to 48.15 cases per million residents. The city posted 58 new cases, with the cumulative tally in the metropolis crossing the 31,000 mark. See below.

9) At the neighborhood level, the health district comprising Verdun, Côte St-Paul, St-Henri and Pointe-St-Charles — a sub-region that's home to eight schools where #COVID cases have been identified — recorded the greatest number of infections Thursday, nearly a dozen. See below.

10) These rising trends suggest Quebec must do a lot more to lower community transmission. Instead of paying police overtime to patrol bars, why not close drinking establishments temporarily? Why not require students to wear masks in class? End of thread and stay safe everyone.