wg48temp9
National Hazard
Posts: 783
Registered: 30-12-2018
Location: not so United Kingdom
Member Is Offline
|
|
Coronavirus pandemic model
I found a model for the pandemic on Semantic Scholar
see Attachment: corvir-model-4c6ac7af8e7681ac8d7804f9b63fab2d8e27.pdf (117kB)
This file has been downloaded 380 times
Its mathematically simple growth model using basic reproduction parameter R. I would have expected most governments to be using a more complicated
model but I guess with populations of millions it works sufficiently well to produce the graphs for the politicians. Below is a graph from the paper.
PS: I am interested in a model that shows the long term infection/death rate. I guess it would have to include a finite population, a decreasing R as
the population become resistant and a sub population of super spreaders.
[Edited on 4/13/2020 by wg48temp9]
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
|
|
|
Chemorg42
Hazard to Others
Posts: 103
Registered: 12-11-2019
Member Is Offline
Mood: Concentrated
|
|
A growth model!?, Really?
I would have thought an agent based model running on a powerful processor would be more accurate in simulating Covid19's particular characteristics.
However, I guess that the accuracy of such a system breaks down as population size increases.
I myself considered creating a simulation to model the spread through a crowd (using 2m radius, occasional "Discharges" of infectious material from
the infected, and other statistics I have not found.) Just an idea.
Anyone who is not shocked by quantum theory has not understood a single word. (attributed to Niels Bohr)
I think I can safely say that nobody understands quantum mechanics. (Richard Feynman)
|
|
|
j_sum1
Administrator
Posts: 6320
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
3blue1brown
Basic explanation of a simple model and the parameters that are critical in describing a pandemic
https://youtu.be/Kas0tIxDvrg
Simulation and analysis of more realistic scenarios and illustrating the effect of modifying human behaviour.
https://youtu.be/gxAaO2rsdIs
Presumably the models being used to inform government policies are more sophisticated than this but they will also be very susceptible to minute
changes and the effect of randomness. In other words, the mathematical models can be scarily close to real data but the situation is still chaotic
(mathematically).
Anyway, these videos are both excellent and worth the half hour or so to watch.
|
|
|
sodium_stearate
Hazard to Others
Posts: 255
Registered: 22-4-2011
Location: guard duty at the checkpoint
Member Is Offline
Mood: No mask.
|
|
It's all seriously cooked data
The only, and let me repeat THE ONLY data
about this debacle that is not being cooked
is the total cumulative deaths resulting from it.
Even that is sketchy because many are untested,
and simply assumed to be caused by the current pandemic.
In short, we likely will never know the truth.
"Opportunity is missed by most people
because it is dressed in overalls and it
looks like work" T.A. Edison
|
|
|
j_sum1
Administrator
Posts: 6320
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
I don't know that you can support that assertion. Certainly there is evidence that China is concealing the true situation. The same can be said for
Turkmenistan and some other nations. As always, the full picture is limited by testing limitations.
But, at least where I am, the numbers seem to be a good representation. There are some troublesome clusters and leaky borders. But in general, the
number of daily new cases is dwindling. There is some hope that we can ease restrictions soon and operate a test and isolate strategy. Reporting seems
to be pretty good. Public understanding may be less so.
[edit]
In any case, the OP is about modelling rather than data reporting.
[Edited on 14-4-2020 by j_sum1]
|
|
|
sodium_stearate
Hazard to Others
Posts: 255
Registered: 22-4-2011
Location: guard duty at the checkpoint
Member Is Offline
Mood: No mask.
|
|
Understood. I will add that the best way to
analyze any model's faithfulness to reality is by
making a direct comparison of what the model predicts
versus what actually occurs.
The core issue here is that deaths are occurring.
Unless the cause of each death is properly tested,
there is no solid baseline to work from.
Accurate scientifically based modeling, working in
conjunction with thorough, scientifically based
testing is the only way forward here.
"Opportunity is missed by most people
because it is dressed in overalls and it
looks like work" T.A. Edison
|
|
|
j_sum1
Administrator
Posts: 6320
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
I think we are on exactly the same page here SS. I would love to have the confidence of data that I knew was both compehensive and 100% accurate.
But that is not the case for even idealised sampling never mind the sampling that occurs in situ in the middle of a crisis with scarce resources.
Here in Aus we appear to have passed over the bump. The number of reported new cases per day is the same as what it was exactly a month ago. And so
people are (with some logic) saying that we have passed the worst and now it is time to ease up. What they don't appreciate is that exactly one month
ago is when restrictions were put into place and we were experiencing exponential growth. If we revert too soon we could easily have exactly the same
scenario that we had a month ago and we would have to brace ourselves for a second wave with a whole new round of deaths. That seems to be the
situation that Singapore may be facing.
I do not think pandemic models are good for predicting outcomes. The situation is too volatile for that and there are a large number of unknowns when
it comes to human behaviour. What models do well is predict the kind of patterns that can be expected and evaluate the probable
effectiveness of various mitigation strategies. Clearly, if numbers are low enough, test and isolate combined with contact tracing and border control
is likely to be the most effective as well as the least disruptive to day to day life. I would like to think that we will get to that stage soon, but
realistically I think it may be another month minimum.
|
|
|
sodium_stearate
Hazard to Others
Posts: 255
Registered: 22-4-2011
Location: guard duty at the checkpoint
Member Is Offline
Mood: No mask.
|
|
I personally think that the world's humans are
now in this scenario for the foreseeable future.
(In for the long haul)
As everyone else does, I too hope that it can
be speedily eradicated.
However, considering similar diseases such as
the flu and the common cold, this new and recent
virus is most likely here to stay as an added
menace to the long list of diseases.
That is a list of diseases which can be to some extent
mitigated. I predict some degree of mitigation, given
a sufficient amount of time and effort. Years perhaps.
"Opportunity is missed by most people
because it is dressed in overalls and it
looks like work" T.A. Edison
|
|
|
SWIM
National Hazard
Posts: 970
Registered: 3-9-2017
Member Is Offline
|
|
If it doesn't form new strains quickly like the flu it is very likely a vaccine that just needs being taken on a regular schedule will do the trick.
Of course some cases will still happen, so they'll do quarantines like it's 1939.
We haven't had much in the way of casually communicable disease epidemics lately, but 80 years ago they'd lock everybody in the house and nobody gets
out until the quarantine period is over. There was a city or county employee who'd come by and nail a sign up to warn people.
You don;t want to ignore that sign. If you go in, you stay.
If you're some unobservant delivery man who just walked in, well now you're a resident and not leaving until the health department says so.
This happened ALL THE TIME in the USA for things like measles, polio, etc.
It's how these things are handled, but we haven't had to all that often lately.
That may well change.
[Edited on 14-4-2020 by SWIM]
|
|
|
Twospoons
International Hazard
Posts: 1324
Registered: 26-7-2004
Location: Middle Earth
Member Is Offline
Mood: A trace of hope...
|
|
Quote: Originally posted by SWIM  | If it doesn't form new strains quickly like the flu it is very likely a vaccine that just needs being taken on a regular schedule will do the trick.
[Edited on 14-4-2020 by SWIM] |
Well, looks like the first major mutation may have been found.
https://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=12324650
Helicopter: "helico" -> spiral, "pter" -> with wings
|
|
|
clearly_not_atara
International Hazard
Posts: 2787
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
What has been surprising to me about this pandemic is that regardless of political affiliation everyone is being so impatient. There will be many
months, even years, after the pandemic when we will do retrospective analyses and try to find unreported cases/deaths, figure out what
should/shouldn't have been done (in hindsight), and so forth. I think we will eventually get pretty close to the truth. The truth can't hide forever.
|
|
|
sodium_stearate
Hazard to Others
Posts: 255
Registered: 22-4-2011
Location: guard duty at the checkpoint
Member Is Offline
Mood: No mask.
|
|
What I find most surprising is the fact that the last
big pandemic was in 1918.
That was 102 years ago.
Medical science is constantly crowing about how
advanced it is now.
To me, it does not seem to be nearly as advanced as
it claims to be.
"Opportunity is missed by most people
because it is dressed in overalls and it
looks like work" T.A. Edison
|
|
|
j_sum1
Administrator
Posts: 6320
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
I think that medical advancements have come an awful long way. I have just had my pelvis bolted together and am expecting a fully recovery with no
long term symptoms. My injuries 102 years ago would leave me lame, or more likely, dead.
Treatments have indeed come a long way. Pandemics are a public health issue and are not in the same category. Apart from a couple of scares, we
really have not had much practice at dealing with this kind of thing. Mistakes have been made and are likely to continue. The post-pandemic learning
and future-proofing will be critical.
Here is a list of some some significant advancements and also some particular hurdles that have had to be overcome. This may put things into
perspective.
Our world has become a lot more mobile than it was 100 years ago. This has made managing the pandemic a lot more complex.
There has been, especially in the early stages, a lot of confusion and misinformation about the disease and the pandemic. There is no doubt
that this has contributed to policy mistakes by governments. It has also contributed to people not fully understanding the situation and not taking
it seriously or otherwise having a disproportionate response.
This particular disease is a combination of high infection rate, low level symptoms for most and high mortality rate for those who are seriously
affected. This combination is the worst possible for containing a pandemic.
Mathematical modelling and simulation methods have never been better. They can inform public policy and facilitate good decision-making.
Diagnostic tests are available in a way that was just not possible in 1918. Sure, we would like more, like them faster and like them more
accurate. But the information they give has been extremely valuable especially for contact tracing. This was something that was just not possible
100 years ago.
The ability to develop and test new treatments or modify existing treatments has never been better than it is now. The speed with which
numerous organisations in the capitalist West have mobilised to create drugs and treatments is remarkable. The scale of this has not been seen
before.
Likewise there are good reasons to believe a vaccine will be developed in record time. Now, this might not eventaute. Coronaviruses are
notoriously tricky. But there is optimism and a large number of people working on it. The science is well developed and, thanks to SARS, we are not
needing to start from square one.
We may wish to complain and there are variations across countries. But as a rule, the world economies are more robust and better resourced than
was the case at the tail end of World War 1. Sure there is likely to be some repercussions, but the ability for many communities to bounce back is
better than a century ago. The biggest concern here are high-density, low wealth nations such as Bangladesh and Indonesia which could potentially
suffer serious impact without the resources to respond.
I hope this is a fair assessment. It is complex and there are multiple factors. But I don't think a lack of medical advancement is the key operative
here.
|
|
|
arkoma
Redneck Overlord
Posts: 1761
Registered: 3-2-2014
Location: On a Big Blue Marble hurtling through space
Member Is Offline
Mood: украї́нська
|
|
can't stop random code, ask Bill gates.
"We believe the knowledge and cultural heritage of mankind should be accessible to all people around the world, regardless of their wealth, social
status, nationality, citizenship, etc" z-lib
|
|
|
sodium_stearate
Hazard to Others
Posts: 255
Registered: 22-4-2011
Location: guard duty at the checkpoint
Member Is Offline
Mood: No mask.
|
|
Certain types of medical science have advanced by a very significant amount during the past 102 years.
The way I see it, orthopedics is one of those categories
that has made significant advances.
So, for bodies that have broken bones, cuts, lacerations,
wounds of many types, yes, the knowledge and technology
has advanced significantly during the past 102 years.
However, I do not see the same amount of advancement
in the area of prevention and/or mitigation of
infectious diseases. The way that looks to me is that civilization
is still pretty much in the dark ages.
"Opportunity is missed by most people
because it is dressed in overalls and it
looks like work" T.A. Edison
|
|
|
Sigmatropic
Hazard to Others
Posts: 307
Registered: 29-1-2017
Member Is Offline
Mood: No Mood
|
|
Now for some actual models. https://science.sciencemag.org/content/early/2020/04/14/scie...
Haven't read the entire thing, yet, but it seems to me too much variables are unknown. That then gives you all these possible outcomes.
Edit: Discussion part is a gold mine in my mind. Let's hope for some favorable variables as I sure do not want to live in the world of fig 6a.
[Edited on 15-4-2020 by Sigmatropic]
|
|
|
clearly_not_atara
International Hazard
Posts: 2787
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
S_S: You don't consider the discovery of penicillin, sulfanilamide, streptomycin, chloramphenicol, isoniazid, chloroquine, nalidixate, dapsone,
polymyxins, vancomycin, chlortetracycline, erythromycin, artemisinin, amantadine, miconazole, natamycin, oseltamivir, saquinavir and sofosbuvir to be
"advancement in the area of mitigation of infectious diseases?"
|
|
|
karlos³
International Hazard
Posts: 1520
Registered: 10-1-2011
Location: yes!
Member Is Offline
Mood: oxazolidinic 8)
|
|
Lets not forget the golden antibiotic drug ceftriaxone, which is a drug I would even say that it saved my life from a spirochaete infection(don't mean
syphilis)!
Medicine got really far from over hundred years ago, just not in each and every single issue, we just have started to battle virus infections properly
and effective, but for everything else? Those things we have mostly very well under control.
|
|
|
sodium_stearate
Hazard to Others
Posts: 255
Registered: 22-4-2011
Location: guard duty at the checkpoint
Member Is Offline
Mood: No mask.
|
|
Fair enough. I'll amend my previous statement
to read "We are still in the dark ages with viruses"
"Opportunity is missed by most people
because it is dressed in overalls and it
looks like work" T.A. Edison
|
|
|
wg48temp9
National Hazard
Posts: 783
Registered: 30-12-2018
Location: not so United Kingdom
Member Is Offline
|
|
I built a pandemic simple growth model using Mathcad, using a reproduction parameter (R) an incubation duration parameter (time to become
infectious), an infectious duration parameter and a recovery/death duration parameter. To make the model manageable those parameter were converted to
rates per step of the model. That did not seem to work so I changed to two parameter a reproduction rate and a recovery/death parameter. ie a
Susceptible-Infected-Recovered or removed (SIR) model. I got that to produce a bell like curve of the number of infected people. The cunve looked like
the product of an exponential increase and an exponential decay to zero which suggested an analytical solution . I attempt to find the solution but
failed. I did find paper with the analytical solution I am not surprised I could not find it. Attachment: pan-equations-1403.2160.pdf (219kB)
This file has been downloaded 394 times
One thing I noticed with my model was it would produce oscillating results for some R values greater than one. That caused by the classical
instability in digital loop systems when the loop gain is greater than one. That reminded me of a video I had seen by Veritasium. I manged to find it
again https://www.youtube.com/watch?v=ovJcsL7vyrk&t=155s
When I first watched that I thought it was interesting but not necessarily relevant to instability in digital feed back systems but I am curious now
how the detail of spectrum of the oscillations are created.
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
|
|
|
wg48temp9
National Hazard
Posts: 783
Registered: 30-12-2018
Location: not so United Kingdom
Member Is Offline
|
|
Below is paper describing the London School of Hygiene and Tropical Medicine (LSHTM) Pandeic model.
Attachment: Contagion-The-BBC-Four-Pandemic.pdf (1.2MB)
This file has been downloaded 426 times
I am wg48 but not on my usual pc hence the temp handle.
Thank goodness for Fleming and the fungi.
Old codger' lives matters, wear a mask and help save them.
Be aware of demagoguery, keep your frontal lobes fully engaged.
I don't know who invented mRNA vaccines but they should get a fancy medal and I hope they made a shed load of money from it.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
