When a danger is growing exponentially, everything looks fine until it doesn’t [COVID19] [ed]

Washington Post ^ | March 10, 2020 | Megan McArdle

[C19fan]

There’s an old brain teaser that goes like this: You have a pond of a certain size, and upon that pond, a single lilypad. This particular species of lily pad reproduces once a day, so that on day two, you have two lily pads. On day three, you have four, and so on.

Now the teaser. “If it takes the lily pads 48 days to cover the pond completely, how long will it take for the pond to be covered halfway?”

The answer is 47 days. Moreover, at day 40, you’ll barely know the lily pads are there.

That grim math explains why so many people — including me — are worried about the novel coronavirus, which causes a disease known as covid-19. And why so many other people think we are panicking over nothing.

[winslow]

Your numbers are wrong. Average age of deaths are not 80. The mortality rate is around 3.5% which is around 35 times higher than the flu.

[DoodleBob]

Agreed. Let's use some actual data vs made-up "global warming"-esq hyperbole.

Here is the plot of SARS cases over time:

Clearly, the rate of increase in cases is high early in this saga, but at some point it leveled off. The lily pads didn't overtake the pond.

Let's look at the ACTUAL Case Fatality Rate for SARS for select countries:

Now, to be sure, the CFR is high initially but then it declines (due to a variety of things like improved controls, better medical care, etc.). Even in Taiwan where it rose initially, it eventually leveled off.

Yes, I know...Coronavirus isn't SARS. But Coronavirus isn't TEOTWAWKI...even if you don't trust the PRC data, in the Western World especially in non-Italian European countries, the numbers aren't akin to lily pad overtake. Even in the US, while we are seeing growth in cases, we're not seeing wide swaths of the citizenry being taken out.

Of course...wash your hands, bump elbows, and maybe pick up an extra case of water and bags of chips. Keep watch and be vigilant. But anyone with a browser, a calculator, and some good reading comprehension will understand the hype is greater than the human toll.

[FreeReign]

Your numbers are wrong. Average age of deaths are not 80.

The average age of death from COVID-19 in the US was 80 as of yesterday. Not sure if the poster meant to say that or not. I have not idea what it is for the world.

[novemberslady]

:)

[HamiltonJay]

Where do they find these chicken littles?

Look the Infection rate is slowing worldwide. 1 precisely 1 person under the age of 20 has died from this.

4000 or so worldwide.

If this was the end of days virus you would see infection rates at 70-80 or 90% on these cruise ships and you aren’t.

Folks really need to calm down.

[FreeReign]

When a danger is growing exponentially, everything looks fine until it doesn’t [COVID19] [ed]

The death rate from COVID-19 in the US since March 1 has been fairly flat, not exponential. So that would be one important statistic that contradicts the Fake News Washington Post headline about the danger being exponential.

As far as the rate of the number of people who are getting COVID-19 in the US, its hard to say if it's exponential, because the data is skewed by the lack of test kits that were available early on and the large recent increase in the availability of test kits.

[jdsteel]

“ Without any measures to prevent its spread, coronavirus cases will increase exponentially until every person who is susceptible to catching the disease has caught it.”

That’s nonsense. I refer you to H1N1, SARS, MERS, AIDS, Ebola and even the common cold or flu.

[exDemMom]

That’s nonsense. I refer you to H1N1, SARS, MERS, AIDS, Ebola and even the common cold or flu.

In every one of those situations, measures were taken to control spread. Every one. In addition, most of those are not pandemic capable. SARS and MERS, for example, infected the deep respiratory tract, meaning that they caused more severe illness and high mortality, but were not very contagious. AIDS and Ebola are bloodborne pathogens, which are spread by contact with bloody fluids. H1N1 spreads quite readily; the annual vaccine contains an H1N1 strain to limit its spread. The common cold does not kill people, so is a nuisance but not a public health threat.

My point is that if we do not take active steps to control transmission, both on the public health and on the individual levels, the entire population is what we call naïve--no one has immunity, and exposure is very likely to cause infection.

Oh, FYI: the spread of *every* disease is exponential. No disease in history has ever appeared in every susceptible person simultaneously, so the spread cannot be anything other than exponential.

[jdsteel]

As stated before, “exponential” is not correct. “Bell Curve” is correct.

You also said: “Without any measures to prevent its spread, coronavirus cases will increase exponentially until every person who is susceptible to catching the disease has caught it.”

And that remains nonsense. It’s safe to assume that no one has immunity and as such 100% of the human population is susceptible. To think 100% of the human population WILL catch it is ridiculous.

[exDemMom]

As stated before, “exponential” is not correct. “Bell Curve” is correct.

Once again, wrong. A growth curve describes biological functions such as the growth of bacteria, of cells in culture, of populations, etc. All growth curves are exponential. In the initial phases, the curve is almost flat. But then it enters a linear phase where the increase in numbers continues unabated until resources start to run out. In the case of coronavirus, the "resource" would be non-immune people. At that point, the curve levels off and then begins to fall as resources become depleted.

This links to an academic explanation of a growth curve. Scroll down to fig. 2 for a depiction of a typical growth curve. A mathematical example is further down.

A bell curve is a statistical function that describes the distribution around a mean of a measured quantity. It has nothing to do with growth of anything, but with measured quantities. It can be used to determine the average and standard deviation of scores on a test, how precisely a machine that is designed to pack 3 oz. bags of peanuts is actually performing, etc. It is a completely different mathematical function than an exponential growth curve.

As I previously said, without control measures, the virus will spread until every susceptible person has caught it. There are plenty of viruses (like other cold viruses) that 100% of people have caught, so your assertion that the coronavirus would never reach 100% coverage is not based on reality. The purpose of the control measures is to arrest the spread of the Covid-19 and force it into decline long before its natural course takes place.

[jdsteel]

“ As I previously said, without control measures, the virus will spread until every susceptible person has caught it.”

As I have said, that is nonsense. There are many variables, including distance and human behavior.

And as far as the bell curve is concerned, listen to a rebroadcast or the 3:30 Coronavirus event from the White House. You’ll clearly hear the doctor say their desire is to “flatten the curve”.

[SheepWhisperer]

Still spamming eh?

How much do make for each hit to that website
Because that’s all you post

JR might want to charge to an advertisement fee for this

[exDemMom]

You really do not understand anything about mathematical functions, do you? Or about biology or epidemiology?

An exponential growth curve, i.e. EVERY growth curve, is NOT a bell curve. Calling a growth curve a bell curve is like calling a brick “cheese” because bricks and cheese have a similar shape.

Once again, a bell curve describes a distribution around a mean. A standard deviation is the distance from a mean. A bell curve has NOTHING to do with growth.

Of course the doctors the President had talked about flattening the curve. They were talking about flattening the growth curve, not a bell curve.

I have taken the time to explain these technical terms to you. Please act like you are capable of understanding the concepts.

[BunnySlippers]

Bookmark

[cherry]

problem is that so much information has been withheld....

starting with, who brought the virus to that Seattle nursing home?....how many staff got sick, how many patients got sick but had mild cases and how many did not get sick.....we don't have true figures of what is happening....

[Varsity Flight]

Monday comes.

[The Westerner]

Singapore has been exceptional in reporting each case, where the person was exposed, how many days to 1st symptom, even street where person lives. Thailand, Hong Kong, Taiwan also have kept their citizens informed, to the point of “the taxi driver who had a fare on x day at x time” please contact us.

My own city had a case in January. The local government shut down all information after initial reports. It is alarming that the mentality of the officials in this country parallel the mindset of Xi.

[jdsteel]

You are stuck on the fantasy that infectious diseases only grow. The fact is they grow to a point and then decline.

What shape do you think that resembles? A bell or a brick of cheese?

If what you said was true humans would be extinct long ago. So would animals, who also become infected by viruses and don’t have the intellectual capacity to take preventative action.

You may be educated but seem to lack common sense. History, not I, proves you wrong.

[wgmalabama]

You have done a fabulous job of explaining the details and being polite while being insulted. If I remember correctly, aren’t you in the medical field?

Anyway, good answered to try to educate. Too many people don’t understand the risk and why the response. It’s beyond their ability or willingness to understand. Flattering the curve is the only way to not do major damage to the economy, health services, people, politicians, ....

It was a hard upfront decision but one that Europe is going to show us was required.