Here is a nine minute video explaining the spread of the virus using simple math and lots of visuals. If you are one of those people who thinks math is a futile pursuit or that experts are, because of their expertise, unbelievable, this clip is not for you. But for everyone else, it may well be useful.

What I particularly like about it is that it shows rigorously, but clearly, how important changes in personal hygiene and social distancing are in bringing the crisis to an end.

https://www.youtube.com/watch?v=Kas0tIxDvrg&feature=youtu.be



Edited 1 time(s). Last edit at 03/17/2020 03:36AM by Lot's Wife.

Very nice. Even those who don't think math is important should watch it. Maybe it will change their minds.

Yes, we are at a point where elementary prejudices should be re-examined.

Are math and science futile?

Are "experts" part of an elite conspiracy against the common man?

Are vaccines an evil plot?

Is it safe to let 10-20% of a population exist without insurance and basic healthcare?

Are novices the best people to run complex organizations and governments?

It will be interesting to see how US political culture changes as a result of this experience--though the evolution will not be clear for many years.

An addendum.

There's a point in the clip where the narrator explains that if you look at two countries' numbers and see a big difference at a given point in time, it could mean one of two things. First, the country with the lower number of infections may be healthier. Second, the country with the lower number of infections may simply have started its expansion later and hence be at a lower point on the same curve.

Apropos that, the following articles note that the United States is at the point on the curve occupied by Italy two weeks ago. In other words, if things don't get better right away the US could soon find itself in the worst-case scenario.

As Russ Nelson might say, "eat your vitamins."




https://www.cnn.com/2020/03/17/health/us-coronavirus-updates-tuesday/index.html

https://www.cnn.com/2020/03/14/health/coronavirus-asymptomatic-spread/index.html

Here is an article explaining it with no equations.


https://www.washingtonpost.com/health/2020/03/16/social-distancing-coronavirus/

And this one is a little more mathematical

https://www.washingtonpost.com/graphics/2020/world/corona-simulator/?itid=pm_pop

Well, I fear that you have fallen for the "religion of science."

Joke, that.

That second article is excellent, much like the video to which I linked above. There are a couple of things that worry me about this problem, both of them illustrated by China.

China tells us that it has the virus under control. But I'm not yet convinced. The country publishes fake data on all sorts of subjects all the time. A few days ago I was looking at the curve for infections and saw a stunningly tight correlation between actual numbers and a model's predictions (in nerd-speak, the R^2 was miniscule). What bothered me was that in real life you'd expect to see more peculiarities, more breaks in the pattern. It is tempting, therefore, to conclude that the Chinese government "conformed" the data to a model rather than vice versa. Perhaps the reality is messier than we have been told.

Conversely, if one accepts the Chinese numbers are real, is the country out of the woods? Say that China succeeded in containing the virus but that it then escaped to, I dunno, South Korea and Iran and Italy. Or even worse, let's say that North Korea, which says it has no cases, is in fact an impoverished country with terrible healthcare infrastructure and hence has become an enormous Petri dish. What happens when the virus returns from those places to a China that has lifted martial law?

There's obviously value in slowing the spread of the disease so that hospitals and doctors can keep up with it, but I worry about a place like China that may have won the battle in a few areas but isn't prepared for when COVID-19 returns to the entire country from more than one source.

I'm afraid this virus is a big deal.

Yes, and that is discussed in my first link. It notes that China is putting restrictions on people entering China from other countries in order to prevent (or least attempt to) introduction of another wave of infections. The first link makes the point that the US will Probably need to continue some control measures until a vaccine is available in 12-18 months.

I don't think life here is going to return to complete normalcy for quite a while.

And yes, I got the religion of science (and math) a long time ago.

"China tells us that it has the virus under control. But I'm not yet convinced. The country publishes fake data on all sorts of subjects all the time. A few days ago I was looking at the curve for infections and saw a stunningly tight correlation between actual numbers and a model's predictions (in nerd-speak, the R^2 was miniscule). What bothered me was that in real life you'd expect to see more peculiarities, more breaks in the pattern. It is tempting, therefore, to conclude that the Chinese government "conformed" the data to a model rather than vice versa. Perhaps the reality is messier than we have been told."

COMMENT: I did not see what you are describing here, but the tightness between the model and the data does not necessarily suggest bad faith. It could just mean a manipulation of the data set and the model to best identify correlations between conveniently chosen variables. Or it could mean that the model was produced to conform with the data prior to confirmation by successful predictions. It is not uncommon for the data of a social science study, for example, to suggest or motivate a model which is then presented as more or less accurate for future predictions, making the model appear more credible as a predicator than it actually has proven to be.
_________________________________________

Conversely, if one accepts the Chinese numbers are real, is the country out of the woods? Say that China succeeded in containing the virus but that it then escaped to, I dunno, South Korea and Iran and Italy. Or even worse, let's say that North Korea, which says it has no cases, is in fact an impoverished country with terrible healthcare infrastructure and hence has become an enormous Petri dish. What happens when the virus returns from those places to a China that has lifted martial law?

COMMENT: Well, this is why it is up to each country, or social unit, to protect its own through quarantine and isolation. In your example, I believe it would take a significant reinfection to create, or reestablish, a pandemic situation, because at this point in China all of the relevant factors are receding, and presumably those previously infected have generated immunity to reinfection. (I am not sure about this. It would be nice to hear from an expert about the factors and outcomes associated with reinfection.)
______________________________

There's obviously value in slowing the spread of the disease so that hospitals and doctors can keep up with it, but I worry about a place like China that may have won the battle in a few areas but isn't prepared for when COVID-19 returns to the entire country from more than one source.

COMMENT: China has no interest in leaving their population vulnerable, and their scientists are generally as smart as our own in these matters. What may be important is keeping them out of other countries for a time until those other countries have the virus under control. On the other hand, it seems questionable whether once a country is infected, a few international travelers means much, even if some are infected.

Thanks for all of this, LW. Much food for thought.

that was a great video. I like how they visually showed how folks catch the illness by exposure. If we can contain communities the inflection point should come sooner. So basically the best thing we can do is to avoid everyone and barricade Washington, San Francisco and other places.

I hadn't thought about exponential growth always turning into logistic growth patterns. We've got about a month before things turn really bad apparently. The only thing I disagree with is the washing your hands bit. I still don't think that anyone is getting sick by not washing hands. This isn't a stomach bug, or food poisoning. This is an air borne virus, so I don't see how washing hands can make a difference no matter how many bureaucrats, officials at the white house, and smart people, say it does. But very good video anyway.

macaRomney Wrote:
-------------------------------------------------------
> The only thing I disagree with is the
> washing your hands bit. I still don't think that
> anyone is getting sick by not washing hands. This
> isn't a stomach bug, or food poisoning. This is an
> air borne virus, so I don't see how washing hands
> can make a difference no matter how many
> bureaucrats, officials at the white house, and
> smart people, say it does.

Wrong, macaRomney. When it comes to a situation like COVID-19 it pays to listen to the "smart people", like scientists and medical experts rather than going with only our own limited knowledge and experience.

There are aspects of this killer virus that, true enough, they say to date they are not 100% sure about. But expert after expert has said that the #1 action we as individuals can take to protect ourselves, and our communities, is to keep our hands clean. That means frequent thorough handwashing on an ongoing basis (which is a good idea even absent a viral pandemic).

The reason for this is that they believe the virus can live on surfaces for at least hours, likely days. If you touch that surface the virus gets on your hands. It is a short distance from there to your eyes, nose, mouth, through which the virus can enter your body. Experts are stating that you can indeed become infected by the virus getting onto your hands and then touching your face. (They say that we, on average, unconsciously touch our faces 16x/hr).

Why not take a simple measure that is within our own hands, literally, in the face of an infection about which even the experts and leaders among us admit they don't yet know everything?


So, two crucial measures we can take to protect ourselves:

1. Wash our hands frequently throughout the day, using good technique (thorough vigorous scrubbing, including between the fingers and up to and including the wrists, using antibacterial soap and warm water, for at least 20 seconds a time).

2. Consciously avoid touching our face, even if we think our hands are clean (due to the virus being able to gain entry to our bodies via our nose, mouth and eyes).


Here is more information about the mode of transmission of the virus (what is known or postulated to date) as well as how we can protect ourselves.


I. Article in Market Watch:

https://www.marketwatch.com/story/is-coronavirus-airborne-will-it-live-in-my-bathroom-is-it-ok-to-fly-or-eat-out-are-men-more-susceptible-busting-myths-and-confirming-facts-of-covid-19-2020-03-12


Excerpts:

“Human-to-human transmission:

Coronaviruses are most commonly spread from an infected person by:

Coughing and sneezing.

Close personal contact such as touching or shaking hands, followed by touching your own face.

Touching an object or surface with the virus on it, and then touching your mouth, nose, or eyes before washing your hands.

Fecal contamination.

Source: WHO, CDC



“Is coronavirus airborne like measles?

“The jury is out. Thus far, it did not appear to be an airborne virus in the same vein as measles or chickenpox, said Luis Ostrosky, a professor and vice chairman of internal medicine at McGovern Medical School in Houston, Texas. “It’s a virus that travels in droplets. This is very good news. With an airborne virus, one person could infect the whole room.”

“Now for the bad news: Airborne transmission is “plausible,” according to a study (that has not been peer reviewed) posted online this week from scientists at Princeton University, the University of California, Los Angeles and the National Institutes of Health. The researchers concluded that the virus could remain airborne for “up to 3 hours post aerosolization.”

“In the meantime, officials recommend “social distancing” in public spaces. “You would need to touch contaminated secretions to become infected, or to be within six feet of a sick person who is coughing or sneezing,” Ostrosky said. “Studies have looked at how far spit and little droplets fly, and that’s the magic number.” Meeting in outdoor spaces, in theory, could give the virus less of a chance to spread.

“How long can it live in your bathroom?

“It’s not certain how long the virus that causes Coronavirus survives on surfaces, but it seems to behave like other coronaviruses,” the World Health Organization said. “Studies suggest that coronaviruses — including preliminary information on the COVID-19 virus — may persist on surfaces for a few hours or up to several days.”

“Its life span will also vary, depending on the type of surface, temperature and/or humidity. Bathrooms are a welcoming environment for coronaviruses. “Previous coronaviruses can remain viable in cold, moist surfaces up to nine days,” Ostrosky said. So if you are sharing a home with someone who has coronavirus, he strongly advises against sharing the same bathroom.

“Whether you’re on a plane or a train, you are at risk of contracting coronavirus, especially if you are seated near an infected person who coughs or sneezes and/or you touch a contaminated surface and then your face without properly washing your hands.”



II. Information from USA CDC:

https://www.cdc.gov/coronavirus/2019-ncov/prepare/transmission.html


Excerpts:

“The virus is thought to spread mainly from person-to-person.

“Between people who are in close contact with one another (within about 6 feet).

“Through respiratory droplets produced when an infected person coughs or sneezes.

“These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs.

“It may be possible that a person can get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or possibly their eyes, but this is not thought to be the main way the virus spreads.

“How easily a virus spreads from person-to-person can vary. Some viruses are highly contagious (spread easily), like measles, while other viruses do not spread as easily. Another factor is whether the spread is sustained, spreading continually without stopping.

“The virus that causes COVID-19 seems to be spreading easily and sustainably in the community (“community spread”) in some affected geographic areas.

“Community spread means people have been infected with the virus in an area, including some who are not sure how or where they became infected.”


-----

True enough, you do not contract the virus by it getting onto your hands alone. It is when it's on your hands and you then touch your face that you are in danger of giving the virus a chance to enter your body.

The thing is, you have no way of knowing which surfaces you touch may have been contaminated (by any disease-causing entity at any time). So why not take all recommended precautions to protect yourself and those around you?

Regarding your comment, macaRomney, that it's an airborne virus (therefore not transmissible via hands, I understand you to mean) some are saying that they think it *could be* airborne but this needs further study. And it is not the only way, nor the main way, for contagion to spread. They know that the virus exists within droplets expelled by people who have the virus, via their coughing and sneezing. If a person either breathes in some of the droplets or touches a surface that is contaminated by those droplets and then touches their face they are in danger of becoming infected.


III. From an article in "Stat":

"The weight of the evidence suggests that the new coronavirus can exist as an aerosol — a physics term meaning a liquid or solid (the virus) suspended in a gas (like air) — only under very limited conditions, and that this transmission route is not driving the pandemic. But “limited” conditions does not mean “no” conditions, underlining the need for health care workers to have high levels of personal protection, especially when doing procedures such as intubation that have the greatest chance of creating coronavirus aerosols. “I think the answer will be, aerosolization occurs rarely but not never,” said microbiologist and physician Stanley Perlman of the University of Iowa. “You have to distinguish between what’s possible and what’s actually happening.”

-----

Between scientists and medical experts and persons without those qualifications, education, knowledge and experience, which ones do I want to listen to and follow directions from?

For me, that's not a difficult choice. It's science, baby.



Edited 2 time(s). Last edit at 03/17/2020 09:44AM by Nightingale.

I agree it's good advice to wash our hands frequently at all seasons of the year. And yes there is truth in that what we touch spreads a virus from here to there and it can spread that way. But where my thinking differs is that our stomachs are designed to kill off contaminated things in the digestion process.

But you could be right that it doesn't break down viruses well they might continue to live on and on? But if this virus is ingested then we should see symptoms of stomach upset like malaria and yellow fever, and not so much respiratory troubles like pneumonia and bronchitis.

But at any rate I agree, and will wash my hands as suggested :)

The virus travels to the lungs, hence the pneumonia, not to the GI tract.

It may be airborne, Macaromney, but still pretty sticky.

Wash your hands.

agreed!

This was awesome! Yes, the exponential transmission, if interrupted will cause a downward trend. Although it's air borne too, I would speculate hand washing interrupts transmission significantly. True, you can get it air borne, but maintaining that 6 foot distance is crucial.

A study in the Science journal, which used epidemiological research and mobile phone data, suggests there were half a dozen undocumented infections for every one confirmed case in Wuhan at the start of the epidemic. A lot of this is spread by "stealth transmission" where asymptomatic folks unintentionally and unknowingly spread the virus.

Fascinating, Lottie.

It also explains what’s going on with Mormon Church growth.

That's what I love about (not) my Boner.

Bring up a general principle and watch him apply it insightfully to a very different situation!

Doctors ? When we need them we can get them back very quickly.

Nothing to add except that I was watching the video without my glasses on, so it was a bit blurry. I was thinking that whoever did this did a really good job of explaining the technical details. Then I recognized the little pi characters he was using in his animations, and thought "OMG, this is that 3Blue1Brown guy".

And it was, indeed. His tone of voice tends to put me to sleep, but I look at his explanations in total awe. His is IMHO one of the best math sites out there, and it is aimed at "bright high school senior" level. He does fun stuff.

I just looked at some of his titles on youtube. Actually many of his topics are more like 2nd or 3rd year university math major level, though he doesn't get too far down into the technical weeds, because there is only so much you can cover in ten minutes or so.

If you find yourself with time to kill, and made it through algebra in HS, 3blue1brown on youtube is a great place to explore. It may open up a whole new world to you. (yeah, some of it is over my head too. You read stuff over your head long enough, it stops being over your head. Really :)

Another fun one is Vi Hart, who started posting as a HS student, now a college grad. Her videos are deliberately edited to machine-gun speed. If you already are familiar with her topic du jour, that can be fun. If you are actually trying to nail down the details, you need a notepad and a finger on the pause control. She totally obliterates the "girls can't do math" meme.


We now return you to your regularly scheduled programming.

I told you I was the kind of nerd who read math books for fun!

Wile Gluck played in the background ...

Che faro senza Mia Lottie?

I blush.

Love me some O&E!

Remember this https://www.youtube.com/watch?v=RUHHqFTh9BI

That's a good find.

It looks to me like Italy is going to surpass China in total number of deaths within the next few days. The situation in Italy is really dire.

https://www.worldometers.info/coronavirus/

The U.S./Canada border is now closed (by mutual consent of both countries) to non-essential traffic.

I wonder if JS used the example (at 3:42), but reversed it, to get his 40+ wives. His P value must have been lower, since it took him a few years. :-)

Thanks, this brought back high school algebra and college stats classes, long forgotten.

And a bit of calculus, too, although the narrator did his best to hide that.

But yes, it is fun to see math done like that--particularly when relevant to something so topical. That particular presenter has done a number of fascinating math videos.

LW,

"Brain Man: The Boy with The Incredible Brain" is fascinating. I think you'd really enjoy watching him. Youtube.


(Sorry, my link posting leaves a lot to be desired.)

I will look it up. Thank you!

You're welcome. :)

When sorrow is so tragic it can only be expressed in the major mode...

https://youtu.be/C1B85UQT4AY

You are a good man, BYUB.

Do you share my love of Gluck? For some reason he speaks to me a lot more than Wagner, for whom he paved the way. . .

Are you watching the Met's nightly broadcasts, a great break from the virus news?

MET opera on Demand. I’m also watching copious amounts of ballet.

Excellent.

I'm actually enjoying having the children at home. Like everyone else, the crisis will hit us hard. But having everyone here, arranging meals together, reading together, is nice.

Best wishes to you and your loved ones.

My nephew and his wife and child will be arriving at my brother's house in Maryland for an indefinite visit. My nephew is in the restaurant industry in NYC and is currently out of work. His wife can work remotely.

My brother and sister-in-law will be so happy to have them close (especially the grandbaby.) I love how families are pulling together at this time.

Yes, well we'll see if people are still so positive after they've been together for several weeks!

That's wonderful! I've seen some families pulling together around here, too.

Who was it that said:

"IT'S EASIER TO DODGE AN ELEPHANT THAN A MICROBE."