Coronavirus - General Chat - No statistics

[GoSeigen]

How shall we measure this then to work out who is right?

What would you say will be the highest daily death rate for any week in Jan/Feb?

Higher or lower than December?

John

In the UK January will have a lower number of Covid deaths than December and Feb. lower than Jan. Any rise will be small and transient.


GS

[johnhemming]

What is this "virulence" you keep talking about? The virus hasn't changed one bit since it first appeared. It's the same virus. The virus does not spread itself. Only peoples' behaviour has changed.

Gryff

Some people use "virulence" or "infectious" to pertain to the virus in the "environment" which will include the behaviour of the public etc
- I know it's weird, but it means when you read something like that from one of them you've got to do a bit of mental gymnastics to work out what actually is being said (c.f. some people's "herd immunity" definition being "amount of immunity")

-sd

eg

https://sercc.com/FuhrmannGeogCompassFlu.pdf

EFFECTS OF WEATHER AND CLIMATE ON VIRULENCE
In addition to factors such as transmission cycles and host susceptibility, the ability of the
influenza virus to cause infection (i.e., virulence) is also important in the context of
disease ecology and the seasonality of infection

This is the normal definition

https://en.wikipedia.org/wiki/Virulence

Virulence is a pathogen's or microbe's ability to infect or damage a host.

There have been various mutations of the virus, but it is the seasonal change in virulence that I am referring to.

[johnhemming]

It has been argued ad nauseam that the virus is weather-related and seasonal. Therefore, unless there is a Santa heat-wave, the logic is increase not reduction.

It appears, however, that there is a discontinuity in the virulence of the violence caused by the shift in the seasons. Hence I would expect December to be lower than November because there are fewer people to infect.

In this chart of the deaths in England by date of death you can see that the peak date was 18th November which fits with the peak date of admissions of 11th November and that there is now a downward trend. I don't think the downward trend will reverse when the effects of the change of restrictions last week kicks through in 21-23 days from then. We can ignore the last few figures on the chart because they are not accurate.

What we see this chart are two wave both of which are driven by the first differential of the Gompertz curve. The second seasonal one arises because a seasonal shift in the virulence of the virus increases the replication number hence the level of herd immunity needs to go up to a higher herd immunity threshold. Once it hits that point (which may or may not be slightly affected by the second lockdown, but we would have to do some maths to work out how affected it is, it then comes down.

Hence from the peak we have the peak infections being in October. In any event looking at the curve it is obvious that the curve of infections shifted during October. The only logical cause is an increase in the level of community immunity which had a consequence effect on further infections.

[GoSeigen]

Nobody on here has budged in 6 months.
Nobody out there has changed their opinion either.

Wrong. Until July I believed there was a possibility of a new wave of the virus. When it failed to materialise I changed my mind and deduced that the first wave had completed in April and the pandemic was effectively over. I (reluctantly) supported the first lockdown but deride the second.

EDIT: it is very apparent that the virus has been spreading arithmetically (NOT geometrically) since April. Deaths have risen by 0.5m roughly every 3 months. The virus appears to spread more easily in lower temperatures and given the larger Northern Hemisphere population there is a slight bump over the past two months. This will be complemented by low numbers middle of next year.

GS

[swill453]

It appears, however, that there is a discontinuity in the virulence of the violence caused by the shift in the seasons. Hence I would expect December to be lower than November because there are fewer people to infect.

In this chart of the deaths in England by date of death you can see that the peak date was 18th November which fits with the peak date of admissions of 11th November and that there is now a downward trend. I don't think the downward trend will reverse when the effects of the change of restrictions last week kicks through in 21-23 days from then. We can ignore the last few figures on the chart because they are not accurate.

What we see this chart are two wave both of which are driven by the first differential of the Gompertz curve. The second seasonal one arises because a seasonal shift in the virulence of the virus increases the replication number hence the level of herd immunity needs to go up to a higher herd immunity threshold. Once it hits that point (which may or may not be slightly affected by the second lockdown, but we would have to do some maths to work out how affected it is, it then comes down.

Hence from the peak we have the peak infections being in October. In any event looking at the curve it is obvious that the curve of infections shifted during October. The only logical cause is an increase in the level of community immunity which had a consequence effect on further infections.

The huge social changes because of the tightening restrictions/lockdowns will have had, in my opinion, far more of an effect than virulence and susceptibility.

Scott.

[johnhemming]

The huge social changes because of the tightening restrictions/lockdowns will have had, in my opinion, far more of an effect than virulence and susceptibility.

The maths says otherwise. I don't think I can get excel to do this particular maths and I know it will take me a couple of days to write the correct program. Also it is rather obvious from the chart anyway although harder to quantify precisely.

[servodude]

The huge social changes because of the tightening restrictions/lockdowns will have had, in my opinion, far more of an effect than virulence and susceptibility.

The maths says otherwise. I don't think I can get excel to do this particular maths and I know it will take me a couple of days to write the correct program. Also it is rather obvious from the chart anyway although harder to quantify precisely.

Not if you're using traditional western maths

[johnhemming]

Benjamin Gompertz (1779–1865) was an actuary in London

I think that counts as Western Maths. I would not imply either that maths from anywhere else is necessarily flawed. It has to also be reasonably traditional.

[seekingbalance]

The coronavirus is not “more virulent”, however you want to ascribe meaning to that term, in “the colder weather”.

It is transmitted more readily because people stay inside more during cold weather, be that indoors in pubs and bars or indoors at home, indoors at school, indoors generally. Simple as that.

If you meet up with friends outside the breeze disperses your breath, disperses the virus particles, and as long as you are not right in the face of someone who is contagious you have a much greater chance of not catching the virus from them, even over a protracted period.

Indoors, especially in modern buildings with heating, double glazing, you don’t get these breezes, and the airborne virus, riding the waves of our warm moist breath, build up over time. If you visit friends, congregate in a poorly ventilated restaurant or bar, sit next to other kids in school, then it is this time together that is the danger.

Go back outside and no matter the cold, the virus is less likely to get a hold, or even reach you, especially if wearing a mask.

All this talk of the virus being more virulent in colder weather is simply not true. The virus does not care about the weather - it is entirely our behaviours that changes the transmission rates.

This is why the real and only way to stop the spread is to stop people congregating indoors (including on trains and tubes, buses), but it is hard to do in the cold weather. But Governments hate to close schools, so the sacrificial lambs to that priority is to close or restrict pubs, bars, clubs, gyms, restaurants, despite the actions those establishments can and have taken to make things relatively safe. Evidence of this is that we have had zero infections tracked back to either pub or restaurant in my village, but multiple children are currently at home isolating due to transmission at school. Yet the schools remain open.

[swill453]

In the predictions of future deaths, where do you factor in the effects of the ever-changing restrictions? And the changing medical techniques which are improving the survivability of the disease? These are surely easier to model than theoretical concepts of susceptibility, seasonality etc.

Scott.

[Wuffle]

Slaughter the mink, slaughter the children.

W.

[johnhemming]

The coronavirus is not “more virulent”, however you want to ascribe meaning to that term, in “the colder weather”.
It is transmitted more readily ...

We agree on the fact that people catch it more easily. If I were to hazard a guess at why I would think the relative humidity is reduced indoors because people switch on the heating.

It does not, however, matter how people more easily become infected. It does not matter (from the perspective of analysing the disease) how we define the word "virulent". We can avoid using the word. However, for the purpose of this debate we can simply agree that it is transmitted more readily which increases R0 and increases the Herd Immunity Threshold.

When it comes to the definition of the word, however, I prefer to use the word in its standard form. We can look at how Cambridge Dictionary defines it:

https://dictionary.cambridge.org/dictio ... /virulence

the danger and speed of spreading of a disease

Hence I am using the word in its proper form. However, lets just agree that the disease spreads more easily and hence more quickly.

[johnhemming]

In the predictions of future deaths, where do you factor in the effects of the ever-changing restrictions? And the changing medical techniques which are improving the survivability of the disease? These are surely easier to model than theoretical concepts of susceptibility, seasonality etc.

I am sorry, but susceptibility is not a theoretical concept it is perhaps the most important concept. Seasonality is also not theoretical. The government have recently said this is probably a seasonal virus.

These are also easier things to model than the restrictions. That is why the maths has been around for over a century to do this.

[swill453]

I am sorry, but susceptibility is not a theoretical concept it is perhaps the most important concept.

It is theoretical for Covid-19 in as much as you can't demonstrate it from the figures, since there is so much noise caused by all the other factors (restrictions on socialisation and medical advances being the major ones I'd say).

Scott.

[johnhemming]

I am sorry, but susceptibility is not a theoretical concept it is perhaps the most important concept.

It is theoretical for Covid-19 in as much as you can't demonstrate it from the figures, since there is so much noise caused by all the other factors (restrictions on socialisation and medical advances being the major ones I'd say).

It is real. However, it is difficult to work out how many people are susceptible.

[gryffron]

However, it is difficult to work out how many people are susceptible.

We know there are several defence mechanisms. T-cells and antibodies.
The quantity of the initial viral dose also appears to be important. Both to whether you "catch" the virus or not, and to the severity of the disease if you do.

We know, for example, that children rarely spread it to each other. Because they all have strong T-cell response which results in low viral loads spreading in schools. However, they don't necessarily have antibodies. If a child were in prolonged contact with a heavily infected person, working a shift in a hospital ward for example, then they might properly catch the disease.
So are children "susceptible" or not?

Susceptible is not the opposite of immune. There is a big grey area of susceptible. Also heavily driven by behaviour.

Gryff

[johnhemming]

However, it is difficult to work out how many people are susceptible.

We know there are several defence mechanisms. T-cells and antibodies.
The quantity of the initial viral dose also appears to be important. Both to whether you "catch" the virus or not, and to the severity of the disease if you do.

We know, for example, that children rarely spread it to each other. Because they all have strong T-cell response which results in low viral loads spreading in schools. However, they don't necessarily have antibodies. If a child were in prolonged contact with a heavily infected person, working a shift in a hospital ward for example, then they might properly catch the disease.
So are children "susceptible" or not?

Susceptible is not the opposite of immune. There is a big grey area of susceptible. Also heavily driven by behaviour.

Gryff

We can, of course, find a medical defincition of Susceptible
https://www.merriam-webster.com/diction ... 20a%20drug)%20%3A%20sensitivity

the quality or state of being susceptible : the state of being predisposed to, sensitive to, or of lacking the ability to resist something (as a pathogen, familial disease, or a drug

I don't think behaviour comes into this. Furthermore there are learned t-cell responses and innate responses. Arguably someone who uses their innate systems is susceptible because they catch the virus and then potentially spread it whilst someone with a learned response does not carry it for long and probably does not spread it.

Hence I accept there are subtleties relating to susceptibility.

However, in the end we can do our modelling from the Gompertz curve.

[sg31]

'I find it such a curious thing, that even some clearly intelligent people believe this will not result in a spike in deaths.'

No, it's the irony that it will be the rule followers that make it worse.....

W.

I follow the rules, I won't be following the new Christmas rules. I've cancelled Christmas.

[XFool]

Until July I believed there was a possibility of a new wave of the virus. When it failed to materialise I changed my mind and deduced that the first wave had completed in April and the pandemic was effectively over. I (reluctantly) supported the first lockdown but deride the second.

One simple question. WRT the "possibility of a new wave of the virus" (which "failed to materialise"), how do you interpret this model in the context of the current COVID-19 situation in the USA?

[gryffron]

Or indeed Wales. Where there is clear correlation between restrictions and spread.

Wales imposes circuit breaker lockdown - disease decreases.
Circuit breaker lockdown ends - disease increases.
Restrictions re-imposed - ... well we'll have to wait and see. But I know where my money's going.

Gryff