The Canadian government has been criticized for lack of transparency on COVID-19. But since politicians’ reflexive secrecy often hides embarrassing ignorance not inconvenient knowledge, here’s what we and they need to make intelligent choices.
First, à la Donald Rumsfeld, we must realize what we don’t know. We’ve all seen those colourful charts about whether we’re flattening the curve, and apparently not really because the number of “cases” keeps rising fast. But actually they show “identified cases” which, absent widespread random testing, tell us something about serious cases but nothing about total numbers so nothing about the trend. If the pandemic spread silently for months we may already have “flattened the curve” of total cases even as hospitalizations continue to rise.
We also know less than we think about how deadly SARS-CoV-2 is because of the crucial distinction between two terms we should all be familiar with, case fatality rate (CFR) and infection fatality rate (IFR). As the BBC recently explained, CFR means “the proportion of people who die who have tested positive for the disease,” while IFR means “the proportion of people who die after having the infection overall.” Since in a crisis doctors focus on testing those with serious symptoms, CFR exaggerates lethality.
So does a common error the BBC fell into. It said CFR “describes how many people doctors can be sure are killed by the infection.” Not even close. The number of people who die after testing positive for diabetes tells you nothing about how many people doctors are sure were killed by it. Many die from cancer, accidents, infection or multiple comorbid causes.
So CFR is too high because someone with terminal cancer and chronic emphysema who dies with COVID-19 certainly didn’t die of it alone even if it hastened their death. But it’s also too low because if an accident victim bleeds to death because the ER is overwhelmed by pandemic cases, they died of COVID-19 without getting it. (And because doctors rushing to save the sick won’t test everyone who dies.)
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See Also:
(1) Is the COVID-19 pandemic going to lead to a second wave of heart problems?
