coronavirus, COVID-19, Theresa Tam, Justin Trudeau

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Normalcy will not return as before until a COVID vaccine has been developed, the Prime Minister admitted in his daily briefing.

Without remedy on the immediate horizon, the news was as dark as the April gusts that served as the backdrop for Justin Trudeau’s dark update.

On Thursday, Statistics Canada announced that its March survey indicated the loss of one million jobs, bringing the unemployment rate to 7.8% for the month. Even that minimized the seriousness of the situation, as 5.47 million Canadians have asked for emergency assistance since March 15. The April job report will not be for the faint hearted.

The Parliamentary Budget Officer added his harsh news, saying that the federal deficit should reach $ 184 billion this year – 8.5% of GDP – thanks, in part, to $ 2,000 a month in intervention assistance. emergency, which he says will cost $ 22.3 billion.

These figures were gloomy but were at least delivered directly, unambiguously.

Prime Minister Justin Trudeau holds his daily press conference on COVID-19 at Rideau Cottage in Ottawa, April 9, 2020.


Blair Gable / Reuters

This was not the case with the federal government’s best estimate of how the virus is likely to play out on the health front.

Public health modeling, like opinion polls, should be used because a drunk uses a lamp post – for support, rather than for lighting.

Scientists hate models, for the obvious reason that they have the potential to make them look like idiots in hindsight.

Horacio Arruda, director of public health for Quebec, said that models predicting the course of COVID-19 would have as much scientific veracity as a horoscope – the day before the publication of the projection model of his department at the request of his Prime Minister.

Theresa Tam, Canada’s chief public health officer, clearly has an equally bleak view of the astrology of virus prediction.

By publishing the data from her agency, she warned that the model was “imperfect” and “not a crystal ball”.

This reluctance was reflected in a report that was, at best, confusing, and at worst, misleading to anyone who followed.

Precise numbers can be as precise as astrology, but epidemiology is not a pseudo-science

The Public Health Agency has had the audacity to offer a direct forecast of how things might happen next week – an increase in the number of cases to around 27,215 from the current infection rate of 18,447, and an increase in the number of deaths between 500 and 700 from 401 Wednesday.

After that, things got blurred.

The agency has offered a range of possibilities – suggesting an 11,000 death toll if 2.5% of the population is infected, or 22,000 if 5% of Canadians fall ill. These have been cited as the best scenarios.

If “weak controls” are put in place – ie lax social distancing and a small percentage of cases and their contacts localized and isolated – the percentage of infection could reach 50% and lead to approximately 250,000 deaths during the pandemic.

If no controls are in place, the model suggests that the infection rate could reach 80% and cause up to 400,000 deaths.

I asked Tam where Canada is or will likely be on this continuum. She was candid: “We don’t know. “

But the implication of the presentation was that, if we carry out the scenario of fighting the epidemic through isolation, travel bans and hand washing, only a relatively small number of people will fall ill and die. To put 11,000 deaths in context, in 2018, 8,511 Canadians died from the flu and pneumonia.

But that’s not how science works, as Tam and his colleagues know. Isolation works because people without immunity have not been exposed to the virus.

As Amir Attaran, a professor at the Faculty of Law and the University of Ottawa School of Epidemiology and Public Health, said when social distancing rules are relaxed, “as they should be one day, “viral transmission will resume.

According to Attaran, the slide in the Public Health Agency’s deck which suggested that vigorous interventions would limit infections to five percent of the population.

“They would not do this unless (the interventions) continue indefinitely until a vaccine is available, which no one expects in 2020,” he said.

The alternative to a vaccine is the development of collective immunity, which would trigger after 40 to 70% of the population has been infected. (The mode of reproduction of the virus at this stage would drop to the point where each person infects less than another person and the epidemic goes out).

The alternative to a vaccine is the development of collective immunity

But for this to happen, somewhere near half of the population of this country has to catch COVID-19.

Extrapolating figures from the Public Health Agency, 1.4 million people would be hospitalized, 460,000 patients would go to intensive care units, and almost a quarter of a million Canadians would die.

Precise numbers can be as precise as astrology, but epidemiology is not a pseudo-science.

Which brings us back to the Prime Minister’s unusual frankness when he suggested normal service would not resume until we had a vaccine.

“Social distancing and isolation save us time before reaching this destination, but they are unable to change destinations,” said Attaran.

The Public Health Agency did not tell this story, preferring mild soap to science and basic products.

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