https://www.wired.com/story/the-promising-math-behind-flattening-the-curve/

Last week I wrote about the alarming math of a viral pandemic. We talked about how infectious diseases spread exponentially, not linearly—and how that can make what seems, for weeks, like a small problem suddenly very, very big. That’s the challenge faced by leaders: Sometimes the only way to avoid disaster is to take action before it seems warranted.

As an example, I used some numbers from the CDC on total cases of Covid-19 in the US. On Monday, March 16, the count was 4,000; by Wednesday it had grown to 8,000. If you carried that out in a straight line, you’d say: Hmm, it’s increasing by 4,000 every two days. Then you’d expect 12,000 cases on Friday and 16,000 by Sunday, March 22. Oh, if only.