1) More than a month after the school year started, Quebec will require high school students in red zones to wear masks in class as of Thursday. But that won’t be mandated for primary school children. In this thread, I will argue why children in this age group should wear masks.

2) Dr. Richard Massé, a public health advisor to the government, acknowledged that “there is some transmission (of the #coronavirus) in primary schools, but it’s much more limited than what we see in secondary schools.” Massé did not cite any statistics to back up his assertion.

3) In the absence of stats from the government, let me provide some #COVID19 figures by age group drawn from the Montreal public health department from Aug. 25, just before the start of the school year, until the most recent date available, Oct. 4. The stats are quite revealing.

4) First, the stats show that the age group that's posted the fewest #COVID19 cases in Montreal since Aug. 25 are those who are at least 80 years old: 120 new infections. The number of positive results in that demographic grew by just 1.74%, the lowest increase of any age group.

5) In contrast, the demographic posting the greatest number of cases is aged 20 to 29. This group recorded 1,707 #COVID cases during this period. Unlike the increase of 1.74% by the oldest group, this demographic reported a rise of 41.2% — what was expected by health authorities.

6) This suggests transmission of the #coronavirus is now much more heightened among 20-to-29-year-olds than among those aged at least 80. But there are two other demographics that are observing even greater percentage increases: elementary and high school students.

7) The group aged 10 to 19 (mostly high school students) reported 731 positive #COVID results since Aug. 25 — an increase of 58.15%. This suggests that #coronavirus transmission is occurring at a faster rate in this group than among those aged 20 to 29.

8) The demographic aged 5 to 9 (mostly primary students) counted 152 new #COVID cases during this period — an increase of 42.94%. On Sept. 30, the increase in new cases in that group was 28.53%. Thus, #coronavirus transmission is picking up speed in this younger demographic.

9) Lest anyone argue that the absolute number of new cases in this cohort is relatively insignificant, please note that during a nearly 11-week period over the summer, the number of new cases among 5- to 9-year-olds in Montreal was just 74, or an increase of 26.43%.

10) Please reveiw the chart below that shows the increases in #COVID19 cases among all age groups over the past six weeks in Montreal. The data suggest that at the very least Quebec should adopt the Ontario model of requiring that students in Grades 4 to 6 up wear face coverings.

11) Epidemiologist Zoë Hyde, an expert on the subject, had this to say Sunday: “Measures must be taken to…reduce the risk of transmission in schools. At a minimum, this should include the use of face masks by staff and students (including both primary and high school students).”

12) In addition to requiring masks among high school students, Premier François Legault authorized the Health Canada #COVIDAlert notification app Monday. It took a massive resurgence in Quebec for the government to finally act. Why wait for outbreaks in elementary schools to act?

13) Meanwhile, Montreal might be in danger of surpassing the first wave of the #pandemic in new cases. The metropolis’s seven-day average rose to 160.33 #COVID19 cases per million population Monday, amid an uptick in hospitalizations. See the chart below.

14) At the neighborhood level, #COVID19 continues to surge in the centre of the city as well as in the east end of the island of Montreal, as the chart below indicates. The north end of the city is also of concern, a little less so in some parts of the West Island.

15) Finally, Montreal added one more #COVID19 fatality Monday to a death toll that's reached 3,484, higher than those of Portugal (2,018), Austria (818) and South Korea (422) combined. End of thread. Please stay safe, wear a mask in public and maintain #SocialDistancing.

Addendum: According to information I just received tonight from @CovidEcoles, 375 elementary schools across Quebec reported at least one case to date as of last Saturday. In Montreal, it's 104.