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coronavirus math

Fred_Kohlhepp
23-Emerald I

coronavirus math

I recall seeing a number of posts, someone developing the equations for the spread and decay of a disease.  Here we have a direct, practical use for this math.

 

Anybody?

58 REPLIES 58
JeffH1
14-Alexandrite
(To:Fred_Kohlhepp)

Fred,

 

Initially, I set an arbitrary susceptible population at 1M, just to test that units were processing correctly.  In the actual analysis, at the top of page 5, I start using the actual US population, which is N.us := 330 M.   Following aggressive social distancing (I followed the curves out until the infected level was well below zero) the susceptible population drops to, S.asd(365 days) = 329.9M, or just below the initial susceptible population.

Fred_Kohlhepp
23-Emerald I
(To:JeffH1)

Thanks!   Missed that!

LucMeekes
23-Emerald III
(To:JeffH1)

Jeff,

Nice Model, In the Netherlands we're attempting the moderate isolation model. We hope to reach the peak within a week or so.

The problem with full isolation is that you reduce the number of infected 'quickly', but you're left with the menace of re-infection once you relieve the measures. Essentially full isolation can work if there's an outlook on a vaccine in the foreseeable future.

 

As a service to others I've attached your Prime sheet, but translated to Prime 1. So anybody with Prime can open it.

 

Success!
Luc

The problem with full isolation is that you reduce the number of infected 'quickly', but you're left with the menace of re-infection once you relieve the measures. Essentially full isolation can work if there's an outlook on a vaccine in the foreseeable future.

 

Luc,

 

You have put your finger on the problem--the number of people who have not seen the disease and are therefore at grave risk.  (Smallpox decimated the native American indians as my country was explored and settled.)

 

Current estimates for a viable vaccine for this virus run from:

  • three weeks (by the orange clown currently running the United States) to
  • 18 months (by the healthcare professionals desperately trying to get out the truth in spite of the orange clown.)

I suspect the best solution is to try to "flatten the curve" so that we arrive at the end of the infection "bump" just as the vaccine becomes available.  Now, how do we accomplish that?

 

For now:  STAY SAFE

JeffH1
14-Alexandrite
(To:Fred_Kohlhepp)

In my continuing research, I came across two blogs from Tomas Pueyo, who I think has the right amount of sensibility on this issue.  Here are his two blogs that are gaining lots of attention:

 

There's a We The People link where US citizens can sign a petition there to send to the orange clown.

Stay well all!

 

 

regcurry
13-Aquamarine
(To:JeffH1)

Jeff,

I am really interested and impressed with your SIR model. I don't have Mathcad Prime; I only have Mathcad 15 and I was trying to duplicate your results.  I get the same answers through the first

step with no social distancing.  However, when I try to duplicate your social distancing, something must be different between 15 and prime, or I have an error that is not obvious to me.  My results are unchanged from the no social distancing calculation.  I did not include units in my Mathcad 15 sheets.  I have attached only a pdf file because this forum apparently no longer allows attaching .xmcd files from Mathcad 15.  If you have the opportunity, do you see any obvious error.

 

Thanks again for your work and any help you can give.

Reg

Your solve block writes the equations using b , which does not change, and is not one of the function arguments.

Fred,
Thanks much. I didn't notice that.

Stay healthy.
Reg
regcurry
13-Aquamarine
(To:JeffH1)

Jeff,

 

Here is the mathcad 15 file.  The drag and drop doesn't work but the browse does.

Reg

You may also be interested in this Numberphile video.

The modelling is done "live" on the fly - not using Mathcad, though, but the free GeoGebra.

https://www.youtube.com/watch?v=k6nLfCbAzgo

 

A type of epidemic is the financial pyramid

See attachment.

From book the book 2^5 Problems for STEM education

FinEpid.png

 

regcurry
13-Aquamarine
(To:ValeryOchkov)

No wonder I never became rich.🤪

Reg
FDS
12-Amethyst
12-Amethyst
(To:regcurry)

Dear Reg, would you mind sharing your corrected MC 15 file? Best regards and stay safe, Filip 

regcurry
13-Aquamarine
(To:FDS)

I didn't correct anything.  PTC just assured me that I had  a licensed copy since I installed with my Product Code.

Reg
FDS
12-Amethyst
12-Amethyst
(To:regcurry)

Dear Reg, I am sorry I was not clear I ment of Jeff Hennings epidemiologic model. Stay safe. Best regards Filip

Fred_Kohlhepp
23-Emerald I
(To:FDS)

JeffH's file is Prime, was never mathcad 15.

 

The math is not complex, Jeff's explanation in the text with citations is priceless.

 

PDF file attached.

Latest fit to USA data, in Prime 4.0 Express

 

Mitigation does work.  (These numbers still do not match "official" predictions.)

Interesting analysis (in your referenced paper.)  But a question that I didn't see answered in the paper: 

The authors define population sizes {N = S(t)+I(t)+R(t)} for each of their models, but those numbers don't agree in any coherent sense with the country's population.

FredKohlhepp_0-1588422262364.png

(If you let me "turn enough knobs" I'll match any trend.  😉

It is, however, a very interesting discussion:

Most likely, the reason for the
outbreak was that at the beginning of the pandemic, the
United States decided to follow the path of rapid
immunization, i.e. obtaining collective immunity due to a
greater number of patients. The decision not to impose total
quarantine was due to concerns about the economy.

 

Those of us sitting in the middle of this debacle would put a different spin on it, your authors were kind enough to assign at least a conscious choice to our federal government.

 

It is interesting that the percentages of your paper's populations are so low compared to the actual populations.  There are at least four studies that demonstrate that a significant number of people are infected and can transmit the virus but display few or no symptoms, are "unsymptomatic."  Two of these studies claim that 50% of the people shown to be infected have no symptoms.  With that in mind I built (yet another) model to address that.  All of my models to date result in much higher rates of infection until I set the symptomatic percentage of the population to a very low (1.67%) value.  A rough working copy of this latest model (in Prime 4) is attached.  Data from the USA is embedded and compared.  The effects of "social distancing" are included.  And the possible repercussions of relaxing that lockdown can be evaluated.

 

I solicit and appreciate comments and criticisms.

Are you actually blaming the US for the COVID-19 pandemic?👎
Reg

Reg,

 

I believe the coronavirus transferred from animals to humans without human intervention (it wasn't created in any lab) and that this began in China by accident, not by Chinese intent.  

 

My comment about "conscious choice," referred to the paper's comment,"Most likely, the reason for the
outbreak was that at the beginning of the pandemic, the
United States decided to follow the path of rapid
immunization, i.e. obtaining collective immunity due to a
greater number of patients. The decision not to impose total
quarantine was due to concerns about the economy."

 

I believe that the USA and the world as a whole is experiencing a much worse catastrophe than we had to because of the action (or lack of) of our current president and his gang of appointees.  The fact that even now there is no coherent federal level response in the USA, that the state governors are forming coalitions to address this problem, speaks to the complete ineptitude of our current leader.  What three years ago was an embarrassing joke has become . . .  (I can't find the right words.)  I'm ashamed of my country.  I'm ashamed of its response to the coronavirus.  I'm ashamed that there are still people in this country who support this horrible man and follow him.  I'm ashamed that he had enough influence (or somebody did) to keep him from being impeached.

 

Did the USA cause COVID-19?  No, but we could/should have helped keep it from being this bad.

 

Fred

And:contrary to presidential suggestion:

 

Please don't drink (or inject) the bleach!

I am very saddened to see that this forum has devolved into politics.  In the past, I thought it was the only forum that remained true to its original objective: to help others and to share information on the use of Mathcad.  I see it has now followed the same road as other online forums.  Therefore, I am leaving this forum permanently and I have blocked all email coming from this forum.  To those of you who have  helped me in the past with Mathcad problems, I want to give my sincere thanks.  Perhaps in the distant future, I will come back to see if things have returned to the initial purpose.

 

A saddened good bye.😞

Reg Curry

Reg

I'm sorry if I drove Reg away, that was never my intent. I have been tracking the pandemic since February and have been trying to get a model of it for almost that long.  As a result of that attempt I have been spending a lot of my day pulling statistics from the internet; along with the statistics I get stories, claims, boasts, and outright lies.

 

I have been discouraged and disgusted by my own country's actions dealing with the pandemic both at home and abroad.  My comment about Valery's post yesterday degenerated from a simple comment about their model into a rant about my government's handling.  It was one old man, standing on a corner, complaining about something he can do very little to change.  It was never meant to be anything political, never meant to foment an insurrection.  And I followed it with what I intended to be a humorous note about one specific statement by president Trump.

 

I'll miss Reg and his comments and contributions.  This forum needs people like him.  I'm sorry that my outburst drove him away.

Kudoed for such an interesting and informative thread. Nice one, Fred.

Cheers,

Stuart

Covid.png

A businessman went looking for an accountant.  As a test of ability he asked each candidate to calculate his annual tax (based on income.)

 

Candidate #1 said, "You owe $20,000.00"

 

Candidate #2 said, "He's wrong, you owe $12,000.00"

 

Candidate #3 said, "How much do you want to owe?"

Russian version!

A businessman went looking for an accountant.

As a test of ability he asked each candidate to calculate 2x2.

  • Candidate #1 said, "4"
  • Candidate #2 said, "He's wrong, 5"
  • Candidate #3 said, "How much do you want to have?"
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