Here’s the infection trendline Ron DeSantis and Donald Trump are trying to avoid

by | Mar 18, 2020

With the vast majority of the civilized world on lockdown or an outright quarantine, many Americans are left wondering, what’s the point? If 15 days of social distancing and self-quarantining won’t be enough to get past the threat of coronavirus, why destroy our economy for it?

Many also view the virus as just another flu bug, only deadly for a small fraction of the population, and it is those people who should self-isolate and socially distance themselves while the rest of the world goes on about its business.

The problem is the issue of exponential growth, and what that means for our health care systems in Florida, across the country, and around the world. Fifteen days of family isolation will not eradicate the virus, but the hope is that it will “flatten” the curve of infection rates so that hospitals and health care providers can cope with the exponentially growing number of cases.

In mathematical terms, exponential growth rates become ever more rapid in proportion to the growing total number or size. In linear growth, we add a relatively similar number of cases every day, and the total grows, but consistently – the straight line on the chart below. Exponential growth starts very slowly, but begins to explode as time goes on. If you’re not familiar with the rice on the checkerboard story, you might find it enlightening.

Wikipedia also does a pretty decent job of illustrating exponential growth:

In short, while exponential growth seems to start slower than cubic or linear growth, it only takes a little while before growth explodes.

When it comes to biology, any living organism that exists in an environment without predators or competition, with enough resources to sustain growth, will grow exponentially. And the exponential growth won’t stop until one or more of those conditions are removed.

In the case of a virus like COVID-19, human infections will grow exponentially until:

  1. there is no longer any infected person in the population,
  2. regular contact ceases between infected and uninfected,
  3. there are no longer large numbers of uninfected humans available to infect.

Number one will likely never be achieved until we eradicate the virus with a vaccine. Number three is something most everyone in the world would like to avoid. But it’s number two where we have some ability to influence the course of the virus, and medical experts are producing graphs for political leaders like President Donald Trump and Governor Ron DeSantis that look like this:

By implementing social distancing, we aren’t trying to eradicate the virus and protect everyone from getting it. The fact is, until it’s eradicated, the likelihood that large numbers of people will, eventually, contract the virus remains fairly high. The key is that we’re trying to slow down the rate of infection so that it’s spread out over time, rather than happening at all at once.

We are trying to avoid a health care catastrophe in which there simply will not be enough beds to treat those in our population who will desperately need care.

Here’s the current growth trend as of this morning for the United States and for Florida in particular. (Note: Florida’s case numbers are on the right, the national case numbers on the left):

Clearly, the lines for both are starting to look more and more like an exponential growth curve. Still not convinced? Let’s just tick a couple of boxes on our spreadsheet to calculate an exponential growth trendline for us. And for additional context, let’s add in Italy, the world’s current COVID-19 hotspot. For fairness, we’ll match the day of Italy’s 100th infection over the same time period as the United States:

From this trendline, if we take no action and don’t follow social distancing recommendations from our health experts and government officials, we can expect to have 300,000 infections in the United States, and well over 10,000 infections just in Florida by the end of March, just two weeks from now.

The graphs aren’t meant to scare anyone, but to educate. COVID-19 is a deadly disease for some, and entirely mild and treatable for the vast majority of those who get it. What we’re trying to avoid over the next fifteen days is exponential growth of infections that will fuel a medical catastrophe for those who get infected and can’t get care because our medical providers are overwhelmed.

Please consider sharing this story on Facebook to help educate others so they understand the goal of our local, state and national leaders.



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