1) On Saturday, Quebec’s chief public health officer confirmed what was probably obvious to all by now in this province. There is now community transmission of the #coronavirus not just in Montreal but all over the province. In this thread, I revisit the topic of testing.

2) First, though, let me address Montreal, Canada’s #COVID19 hot spot. On Saturday afternoon, Montreal reported two more outbreaks of #COVID19 in long-term care centres, raising the current active total to 24.

3) Montreal also reported a big jump in cases: 424. But I would now like to address the issue of testing. Let us go back in time to March 9. This is when Health Minister Danielle McCann held a news conference in Montreal to announce the #COVID19 screening clinics.

4) We knew at the time that #COVID19 was raging through China and Iran. There were also reports of outbreaks erupting in Italy. What were the Quebec government’s instructions at the time? Only those from Hubei province in China and Iran were to self-isolate.

5) Those coming back from Italy were advised to monitor themselves for #COVID19 symptoms but didn't have to self-isolate. At this point in time, Quebec was recommending testing only for those who had symptoms who were returning. In retrospect, this was a mistake, I believe.

6) Research now shows that people who are pre-symptomatic have been the so-called silent spreaders of #COVID19. Jeffrey Shaman, of Columbia University’s Mailman School of Public Health, estimated that 86% of all infections in China were "undocumented" prior to Jan. 23.

7) The “undocumented” could be those who had symptoms but didn’t get tested, because of a lack of access to testing — or of more concern — people who had no symptoms or such mild symptoms that they decided to just carry on with their daily lives. Source: ProPublica.

8) As we know, South Korea has handled this #pandemic with far more aggressive testing than any other nation. Today, the #COVID19 death toll in South Korea stands at 183, with 10,237 cases — nearly 4,000 fewer than Canada.

9) Yet South Korea reported its first #COVID19 case on Jan. 20. In contrast, Quebec declared its first case on Feb. 28 — more than a month later — of a Montreal-area woman returning from Iran.

10) By March 18, a week after the World Health Organization declared #COVID19 a pandemic, South Korea had already tested more than 250,000 people, and had the capacity to test another 20,000 a day. South Korea’s screening was so widespread that it detected the silent spreaders.

11) Those who were truly asymptomatic, who never had the disease, tested negative. Those had symptoms tested positive. But South Korea also captured the pre-symptomatics: those who would develop #COVID symptoms.

12) These silent spreaders, the pre-symptomatics testing positive, were also isolated. In contrast, on March 9 people returning to Quebec from China outside of Hubei province did not have to self-isolate and they would only be tested if they had symptoms.

13) In retrospect, Quebec should have automatically tested for #COVID19 everyone coming back from China, Iran and Italy, including those without symptoms. Sadly, it’s now too late.

14) Quebec has since shifted its testing strategy. It’s now focusing on high priorities like residents of long-term care centres. It’s also testing health workers, but again, only those who are “symptomatic in direct contact with patients.”

15) Will Quebec also test health workers who don't have symptoms, who might be pre-symptomatic? That's a valid question given that the #COVID outbreak at Verdun Hospital occurred after two doctors who were pre-symptomatic went on rounds, possibly infecting as many as 35 patients.

16) Let me ask the same question another way: Should Quebec also start testing health workers without systems, given that on Friday 175 health professionals in Montreal tested positive for #COVID19, up from 148 the previous day?

17) Ultimately, this is matter of life and death. On Saturday, Quebec reported 14 new #COVID deaths, bringing the total to 75. Please see the chart I created below. End of thread. Everyone, please enjoy your time indoors and practice #PhysicalDistancing.