See how coronavirus is spreading around the world — and what lessons we can take from the countries beating the virus.
One good way to think about the exponential spread of coronavirus is to look at how long it takes for the number of cases in a country to double.
Let’s look at three different scenarios — one in which the number of cases doubles every two days, one where cases double every three days, and one where cases double once every week.
Initially, the differences might look small.
But as time passes the differences increase dramatically.
By week three, the differences are stark — and remember this example started from just one case. Not to mention, the coronavirus pandemic is predicted to run for months.
It’s for this reason that early intervention can have a huge impact. One single infection in the early days of the outbreak can easily scale into hundreds, perhaps even thousands over time.
The flipside, of course, is that every infection avoided early in the outbreak can have a huge positive impact.
What does that look like in the real world? Let’s look first at the source of the outbreak, China.
As you can see, in China the virus initially spread exponentially, with the number of known cases repeatedly doubling in less than two days during the early part of the outbreak.
But it now appears the country has reduced that growth, slowing new cases to a virtual trickle.
Now coronavirus is spreading much more quickly in other parts of the globe.
However, because outbreaks in each country started at different points in time, it’s difficult to compare exactly how, say, Australia’s growth rate compares to China’s in the early days of its outbreak.
So, let’s do two things to help make this a bit easier to understand.
Firstly, let’s narrow it down to a few key countries so we can make it a little easier to read.
And now, let’s change it so that we start tracking cases day-by-day from the moment when each country hit 100 cases. Instead of using the exact date, this brings each country onto roughly the same timeline.
But it’s still difficult to compare the early days of each outbreak, because they’re all so compressed down near the bottom of the chart. To aid with this, we’re going to change the vertical axis of the chart to a logarithmic scale. . . . .