1) Montreal public health authorities revealed on Wednesday that the super transmissible B117 variant is circulating a lot more in the city than previously known, triggering massive #COVID19 screening in some schools. In this thread, I will examine what this means.

2) First, Dr. Mylène Drouin of the public health department noted the city has eight confirmed B117 cases (one higher than provincial authorities have disclosed) and one from the California variant, Cal.20C, blamed for the spike in recently diagnosed infections in Los Angeles.

3) Second, Dr. Drouin added authorities have counted 23 presumptive cases of the B117 variant after initial screening. That means those cases have tested positive for the N501Y mutation on the spike protein of the #coronavirus. Genetic sequencing will confirm the exact variant.

4) Third, Dr. Drouin divulged that a child attending Collège Stanislas in Outremont is suspected of carrying the B117 variant. The private elementary school at Stanislas has shut for two weeks as authorities screen all the students and staff.

5) This all adds up to a worrisome development in Montreal only three days after the government allowed retail stores to reopen. It also explains Dr. Drouin’s sombre disposition at Wednesday’s news conference despite a dramatic drop in #COVID19 hospitalizations in the city.

6) Dr. Drouin noted that Montreal schools have become a driving force in the spread of the #coronavirus since reopening last month, blaming them for the increase in #COVID19 cases among the 0-to-17 and 35-to-44 age demographics, the latter being parents.

7) Since last week, the total number of #COVID19 outbreaks in elementary and high schools in Montreal jumped by 58 to 92. Drouin confirmed that larger outbreaks forced the temporary closing of four schools, including Stanislas. Please see the chart below.

8) By comparison, workplace #COVID19 outbreaks dropped by 67 since last week to 128. Most of that decrease occurred in retail stores, which reopened on Monday. Given the presence of the more transmissible variants in Montreal, one can expect workplace outbreaks to rise again.

9) Thus, Montreal is at a crossroads in the #pandemic, with transmission of the wild type of #coronavirus — that is, the strains that contain no major mutations — on the decline in the community and in hospitals. But at the same time, there is evidence of variants in the city.

10) It’s in this context of the possible propagation of variants that schools remain open and stores have reopened, with just 3% of the population inoculated against #COVID19 and new vaccine supplies trickling into the city. End of thread. Please limit your social contacts.

Addendum: The following includes charts that I made that somehow didn’t fit tonight’s thread, starting with the overall number of cases in Montreal. See below.

Addendum 2: The chart below by the Education Department shows a dip in #COVID19 cases in schools, but an increase in the shuttering of classes.

Addendum 3: The chart below shows a slight decrease in #COVID19 outbreaks in Montreal since last week.

Addendum 4: The last thing anyone wants is emergency room overcrowding in a #pandemic, with variants potentially on the loose. Please see the chart below.