There Is No ‘Casedemic’

Why the rise in COVID-19 cases is very worrying

Pictured: We’re all in this together, and other reassuring slogans. Source: Pexels
Pictured: Not over yet, unfortunately. Source: Pexels

True Cases

My epidemiology mentor, a professor of many years, has a great saying: “remember the denominator”. The denominator of your proportion is the most important part of the equation. Without knowing how the denominator has or will change, we don’t really know anything about the numbers themselves.

Maths is fun! Source: Pexels
Make your own scary map at Our World In Data
Pictured: A changing denominator!

IFR = deaths/true cases

So to work out the true case numbers, we just flip the equation:

true cases = deaths/IFR

Let’s look at an example. Here’s the graphs of cases and deaths for the United States — looks like a ‘casedemic’ at first glance! Cases rising but a much smaller increase in deaths.

Source: Me

Bottom Line

The central thesis of the ‘casedemic’ myth is very obviously false. We know that we must have had many more cases earlier in the year than were recorded — this is not at all a contentious point — and indeed it looks like we are heading for a second March in many places in the world right now.

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