[Petrochemicals (OP)]

Quite a simple one this, yes or no ?

If so should we isolate ourselves from others ? Shun mass gatherings, stop trading ?

[Bored chemist]

Quite a simple one this, yes or no ?

"For every complex problem there is an answer that is clear, simple, and wrong."

https://www.brainyquote.com/quotes/h_l_mencken_129796

If you think epidemiology is simple, you are mistaken.

There's also an implication that we are panicking.
Some probably are. Most are not.
It's probably fair to say that panic isnever a helpful response, given that we are capable of reasoning.

So, the question makes little sense.

"Is [anything at all] a reason to PANIC ?"
No.
It's not even a reason to USE CAPITAL LETTERS.

[wolfekeeper]

Quite a simple one this, yes or no ?

If so should we isolate ourselves from others ? Shun mass gatherings, stop trading ?

No, but the fact that about 100% of the world population is susceptible, and further that it's killing very roughly 1% of those it infects (so it could be expected to kill very roughly 70 million people, comparable or higher than the 1918 Spanish Flu) is.

[Bored chemist]

OK, there's a reasonable estimate that,in the UK there are about 10,000 cases (rather more than the official total- because of limited testing.)
And there are roughly 100 million people in the UK
So very roughly 1 in 10,000 has the virus.

So, if I go to a local football match or concert with 10,000 other people, I can expect roughly 1 person there to have the virus.

It's said that it's unlikely to spread more than a metre or two.
So that's a  dozen or so people within "range" and, of course, not all of them would actually get infected - I'm guessing 1 in 10.
So I ( as a member of the crowd) have a less than 0.1% chance of being in range and, at a guess, a less than 0.01% chance of getting the virus.
And, if I do, I have a roughly 1% chance of death (I'm fifty-odd years old)
So, my chances of dying from going to a gig or concert is about 1 in a million. For most (young) concert goers, it would  be about 10 times less..

Very roughly that's a 0.4 % relative rise in death rate
https://en.wikipedia.org/wiki/Micromort
tells me that background death rates are about 24 in a million per day.

If a typical concert goer travels  10 km by motorbike to the event, they are about 10 times more likely to die in a road accident than from the virus.
(same source)

So, it does not seem to me that we should panic yet.

[evan_au]

I would suggest that there is an optimum amount of panic/concern:
- Organisers of large events (eg > 500 people) should probably cancel them. The Grand Pix was canceled in Australia last week, after several of the competing teams had picked up corona virus on their world travels.
- People should be worried enough to wash their hands thoroughly, and avoid going to large gatherings
- Companies should check out their procedures for teleworking, and permit employees to work remotely (where that is feasible)
- People with colds or coughs should stay home instead of going to work.
       + When corona virus cases are low, the cough probably will be the common cold.
       + But when corona virus cases increase (and I expect they will), there is a reasonable chance that it will be the corona virus, and people should already be in the mindset that they are staying home whenever they have cold symptoms.
      + The point is, the person at home can't distinguish them (without a massive community-wide testing effort)
- The optimum amount of panic will change over time, depending on how many people are infectious, and how many people are immune, whether people are going hungry in their homes, and whether the hospital system will cope in 2 weeks time.
- For areas where there is an outbreak, banning even small meetings (50 people) and closing schools will slow down the spread
- Welding doors shut or shooting people on the street is an excessive level of panic.

So that's a  dozen or so people within "range" and, of course, not all of them would actually get infected - I'm guessing 1 in 10.

This is a big increase of the usual R₀ of the virus. In the usual home/work environment, R₀ for this virus is thought to be around 2-3.
- When you have exponential growth, increasing the exponent even slightly makes a big difference.

The impact here depends on the prevalence in the stadium population.
- If 1 person has it, they might infect 10 at the match
- These 10 will take it to home and work, and infect another 20
- Omitting that 10x multiplier at the football match will really slow down spread of the disease.

Move forward a couple of weeks, and you now have 1% of the people in the ground with the virus - and the next week you now have 10% of the attendees with the virus.
- That is a lot of cases, very quickly; perhaps 1-5% of them will require hospital treatment, and possibly overload the hospital system

It will be a disruption to the normal economics and atmosphere at the stadium, but I suggest that you stay home and watch the game on TV!
- This is only delaying the inevitable...
- Sports competitions will shut down when every team (or their opposing team) has a player with the virus (and the rest of the team has been in contact with the infected player)

[Bored chemist]

I would suggest that there is an optimum amount of panic/concern:

The optimal level of concern is not panic- more or less by definition of panic.

This is a big increase of the usual R0 of the virus. In the usual home/work environment, R0 for this virus is thought to be around 2-3.
- When you have exponential growth, increasing the exponent even slightly makes a big difference.

The impact here depends on the prevalence in the stadium population.
- If 1 person has it, they might infect 10 at the match

Hang on...
What I said was that someone in the crowd exposes about a dozen people round them.
But that of those 12 people, most won't actually be infected- my guess was a tenth of them- roughly one additional person gets infected. An R0 value of 1 over the course of a match

That's very broadly in line with and R0 value of 2 or 3 and, of course, it's very pessimistic.
It's odds on that an asymptomatic, but infected, man at a football match will infect nobody.

If he doesn't go to the match, he's likely to go to the pub, or the library  or whatever.
OK if he tends his garden or just watches telly, that actually reduces the odds of transmission.

[alancalverd]

The average UK death rate is about 2000 - 2500 per day. Given that a proportion of those deaths attributed to COVID already had an underlying serious illness, it's likely that at least in the early stages of epidemic, it will temporarily accelerate their demise but simultaneously reduce the pool of the most susceptible, so any concern about extermination of the species isn't justified.

The real concern is that after a decade of cutting local authority spending, those who have paid their taxes and ought to have reasonable care at home are left to die in hospitals whilst the infection is spread through schoolkids because everyone must have five GCSEs regardless of the harm done.     

[Bored chemist]

because everyone must have five GCSEs regardless of the harm done.     

That doesn't make much sense.

[Petrochemicals (OP)]

Sorry, I really should have made it clear that I was on about the 2017-18 flu season where mortality was 1.25 deceaced per million population per day. Terribly tardy of me.

https://www.vox.com/2018/9/27/17910318/flu-deaths-2018-epidemic-outbreak-shot

This was averaged on a population of 350 million, over 180 days.

[evan_au]

If he doesn't go to the match, he's likely to go to the pub, or the library  or whatever

If there are local centers that cause a local outbreak (eg the local pub, or the local library), it is easy to slow down the local outbreak by closing local sources.

However, if there is gathering of people from many different areas, that increases the chance that some people willl be there from somewhere that has an outbreak, and that people from the gathering will then take it to additional places, causing additional outbreaks.
- Multiple outbreaks across a wide area is harder to control than fewer, more local outbreaks.
- And it has a larger impact on supply of goods and services (people still want to eat, communicate and watch TV, even if they have the virus...)

So the type of gathering is important...
- A local child-care/early education center with mostly local families, where the children associate with mostly their own age group...
- will have a more limited impact than...
- A city university, where students travel long distances daily, and spend time in multiple lecture theaters with different groups of people, only to travel long distances back to different parts of the city (many traveling via public transport)
- A university town like Cambridge with mostly bicycle transport is partway between these extremes

I'm just suggesting that if there is a way of achieving the goals without a mass gathering, that is a preferred solution.
- Broadcasting football games is an established technology & there is an established economic model supporting it
- For schools that have never had to attempt it, Facebook streaming is available. Chemistry classes would need to focus on the theory (or deliver URLs for Youtube videos of the experiments...)

I suggest that the inconvenience of watching a game on the lounge at home has significant benefits over watching the game in an overcrowded hospital emergency waiting room...

[evan_au]

One of the difference between a chemical poison and a biological agent is that:
- the chemical poison gets more diluted the farther it spreads, so you want to dilute it as much as possible
- Biological agents self-multiply, and they multiply more the farther they spread. So you want to limit the spread (or, in an epidemic situation where everyone will eventually get it, limit the rate at which it spreads, so the hospital, ambulance and morgue facilities can keep up)

[Bored chemist]

Terribly tardy of me.

I don't think you know what that word means.

[evan_au]

This author strongly recommends shutting everything down now.

One thing he has right is that everyone is surprised by exponential growth.
- He argues that even a 1 day delay in shutdowns will make a significant difference in mortality
- He shows that shutdowns impact the peak infection & death rate

What do you think?

See: https://medium.com/@tomaspueyo/coronavirus-act-today-or-people-will-die-f4d3d9cd99ca

[Bored chemist]

Nobody seems to recognise the fact that, if you shut everything down, that will also kill people.

[evan_au]

if you shut everything down, that will also kill people.

It will be important to identify critical industries, and to regularly check the people that are moving about to ensure they don't have symptoms.
- As well as emergency services (doctors, nurses, police, ambulance and fire brigade), critical industries would need to include people delivering services like electricity & water, plus those delivering goods like medicines and food
- In some countries, the emergency services may need to be supplemented by national guard or army.

Having an antibody test would assist identifying those who are already immune, and can safely carry out these tasks without spreading the virus further.

[Bored chemist]

If, as is widely suggested, you close the schools, you close all the industries at random (because employees have to take time off to look after kids)
If you don't close the schools then the kids spread the virus to their classmates, and they take it home to their parents and the outcome is pretty much the same.

.

[evan_au]

Some corona virus updates today, from a fairly reputable source:
- It appears that although corona virus mostly has a mild impact on children's breathing, some of them have suffered symptoms of diarrhea. Some children continued shedding virus in stool for 3-4 weeks. Since children (and adults!) are not particularly good at hand-washing, this would seem to be a route that will spread the virus widely in schools and homes.
- In Italy, demand for ventilators far outstrips supply. Apparently, if you are over 60 years of age, you don't get the ventilator - they give it to someone who is equally in need - but younger.
- I heard of a case some years ago in Canada where a doctor had to decide between two patients, and was charged with manslaughter.
- Some hospitals in Australia are rewriting their triage procedures with help from military medics. The military is more familiar with situations where the patients far outnumber the medical staff and facilities.

Listen (10 minutes): https://www.abc.net.au/radio/programs/coronacast/what-can-kids-poo-teach-us-about-coronavirus/12061284

Listen (30 minutes) or read the transcript: https://www.abc.net.au/radionational/programs/healthreport/coronavirus-travel-bans-and-intensive-care/12060354

[hamdani yusuf]

Here is an interesting simulation showing

Why outbreaks like coronavirus spread exponentially, and how to “flatten the curve”

By Harry Stevens March 14, 2020
https://www.washingtonpost.com/graphics/2020/world/corona-simulator/

This so-called exponential curve has experts worried. If the number of cases were to continue to double every three days, there would be about a hundred million cases in the United States by May.

That is math, not prophecy. The spread can be slowed, public health professionals say, if people practice “social distancing” by avoiding public spaces and generally limiting their movement.

Still, without any measures to slow it down, covid-19 will continue to spread exponentially for months. To understand why, it is instructive to simulate the spread of a fake disease through a population.

In one crucial respect, though, these simulations are nothing like reality: Unlike simulitis, covid-19 can kill. Though the fatality rate is not precisely known, it is clear that the elderly members of our community are most at risk of dying from covid-19.

“If you want this to be more realistic,” Harris said after seeing a preview of this story, “some of the dots should disappear.”

And here is how slowing down the spread of the disease becomes important.

This One Graph Shows Why 'Flattening The Curve' Is So Critical For COVID-19 Right Now

https://www.sciencealert.com/dragging-out-the-coronavirus-epidemic-is-important-in-saving-lives

Anywhere from 20 percent to 60 percent of the adults around the world may be infected with the new coronavirus SARS-CoV-2, the virus that causes the disease COVID-19. That's the estimate from leading epidemiological experts on communicable disease dynamics.

Even the best-case scenario using those numbers means nearly 40,000,000 adults will be infected in the United States alone.

Some people may start to feel fatalistic in the face of those kinds of statistics. There are no vaccines and no specific treatments for people who get sick. What's the point of fighting something that's bound to happen anyway? Why not just let the epidemic run its course?

But public health officials and medical professionals have been advocating for rapid and decisive efforts to reduce the transmission of SARS-CoV-2 as much and as early as possible.

The goal is to 'flatten the curve'. Rather than letting the virus quickly rampage through the population and burn itself out fast, the idea is to spread all those infections out over a longer period of time.

Yes, it would potentially prolong the epidemic. But in doing so, public health agencies and the health care infrastructure gain invaluable time to respond to the crisis.

Most importantly, "flattening the curve" provides an opportunity to significantly reduce deaths from COVID-19.

On the steep rise of the epidemic curve, especially when testing capacity is lacking, there is a tremendous burden on health care providers – many of whom will fall ill themselves and be forced to self-isolate, becoming unable to provide care for those in need.

At the same time, there is immense pressure placed on health care facilities where demand for patient care will outpace capacity – things like the number of hospital beds, ventilators and so on – for a significant amount of time.

So yes, even if every person on Earth eventually comes down with COVID-19, there are real benefits to making sure it doesn't all happen in the next few weeks.

How, then, can people 'flatten the curve' via reducing transmission of the coronavirus? At present, with many regions of the United States and other countries seeing community members spreading COVID-19 locally, the world has entered a phase of mitigation to complement efforts to contain its spread.


As a result, we're left with an old but quite effective strategy: social distancing. It means staying out of close contact in crowded public places, avoiding mass gatherings and maintaining space – approximately six feet – between yourself and others when possible.

Social distancing requires changes in how people work, live and interact with each other. It may require canceling or avoiding big events, limiting nonessential travel and rescheduling conferences.

Traditional classroom instruction may have to move to online delivery – already happening in some colleges and universities, though less easy to do for K-12 schools.

To be clear, social distancing comes with a substantial economic cost as people aren't engaged in the same work and life activities that fuel the economy as they were just a month or two ago.

As a result, public health and government officials are faced with balancing the public health push to "flatten the curve" with desires to minimize the impact on the economy.

As the COVID-19 pandemic unfolds, public health experts across the world are collecting data and communicating information as fast as possible in an attempt to provide health care providers, research laboratories, public health agencies and policymakers with the knowledge they need to respond to the emerging threat.

In the meantime, one of the most important things individuals can do for our collective public health is to listen to the experts and follow their advice.

World Health Organization Director-General Tedros Adhanom recently commented that "We need to remember that with decisive, early action, we can slow down the virus and prevent infections."

We're not going to stamp out COVID-19. But by not just throwing up our hands and giving up, people can help address the crisis early, preventing COVID-19 from overwhelming the health care system's capacity to respond effectively.

Matthew McQueen, Director, Public Health Program and Associate Professor of Integrative Physiology, University of Colorado Boulder.

[Petrochemicals (OP)]

Imagine that graph with 85 as the average, dotted line will be into the 200-300 level. Thats what we delt with a few years ago, or were we not able to deal with it ? Should we have shut down every year ?

[hamdani yusuf]

Imagine that graph with 85 as the average, dotted line will be into the 200-300 level. Thats what we delt with a few years ago, or were we not able to deal with it ? Should we have shut down every year ?

The health care system capacity can be temporary increased just like the setup of emergency hospitals in China. When things got under control, they can be dismantled. The need to shut down depends on the severity of the case, but in the end the decision will be made based on cost and benefit analysis of the authorities. Hence electing competent government officials is an important contribution could be made by citizens.