Covid The science behind Covid-19 - All you need to know

Maciamo

Veteran member
Admin
Messages
9,970
Reaction score
3,273
Points
113
Location
Lothier
Ethnic group
Italo-celto-germanic
How is Coronavirus spread and how contagious is it?

According to the CDC, Covid-19 is transferred by aerosol droplets (microscopic drops from respiration in the air) and stays contagious for about 6 hours on most surfaces. But according to a new meta-analysis of 22 studies human coronaviruses are related viruses (SARS, MERS) can persist on inanimate surfaces like metal, glass or plastic for up to 9 days.

Another paper says that at lower temperatures, the virus could survive on a stainless steel surface from 5 to 28 days. It lasted longest in very cold and dry conditions: at 4°C and 20% humidity. So the environmental conditions play a role too.

According to a preprint published last week by researchers at the National Institutes of Health, Princeton, and the University of California, Los Angeles, coronavirus remains viable in the air for up to three hours. That's enough to contaminate a lot of people in supermarkets, buses, trains, air planes, airports, etc. if even just one contaminated person in present.


How dangerous is Covid-19?

It highly depends on a number of variables.

1) Age : Mortality is very rare under 50 years old, then steadily increases with age.

2) Gender : Men are 50% more likely to die than women.

3) Health : Suffering from pre-existing conditions like cancer, chronic respiratory disease, hypertension, heart disease and diabetes all increase the chance of dying from the virus, especially in older people.

4) Lifestyle : Smoking is an aggravating factor, although it is not yet clear how much it modulates the overall risk.

5) Environmental factors : Mortality rates appear to be higher in regions with severe air pollution such as Chinese cities and North Italy.

_111104222_death_ratio_v2640-nc.png



The death rate shown in the BBC graph above is only for severe cases. About half of young and healthy people are asymptomatic or present very mild symptoms and therefore are part of the reported cases, which skews upwards the actual mortality rate. Scientists now believe that the fatality rate is closer to 0.8% instead of the 3.4% originally announced. Based on my calculations, that would give the following mortality rate for each age group:

- 0% under 10 years old
- 0.05% from 10 to 39 years old
- 0.1% from 40 to 49 years old
- 0.3% from 50 to 59 years old
- 0.9% from 60 to 69 years old
- 2% from 70 to 79 years old
- 3.7% from 80 years old

How quickly does Covid-19 propagates?


At present, the virus has spread exponentially, with the number of confirmed cases increasing 10 times every 6 to 11 days depending on the country in the absence of measures of containment or quarantine.


How to follow the diffusion of Covid-19?

The best place is the Wikipedia 2019–20 coronavirus pandemic page, which is updated as soon as new data becomes available for each country. There are also maps and detailed data for each country.
 
Here is an interesting and disputable thought of FrankN from Germany on Eurogenes (I have seen that he is a member here to but inactive). It's IMO worth to mention here:

Let me come back to my "number crunching" exercise. First, I have to excuse for a small yet crucial mistake: I forgot to consider the "dampening effect" on infection rates that occurs after a relevant part of the population has already dealt with the infection. As such, figures will be less dramatic, but still dramatic enough. Here's the update:

Scenario 1: No lock-down, infection rate 2-2.5 (possibly its higher, than figures would be more dramtic):
- Health system overload starting between April, 25 and May, 5
- 20,000 deaths reached by May, 12
- Peak overcome (health system capacities sufficient again) between August,7 and September, 15
- Pandemy runs out between mid-October and late December
850.000-970.000 dead

Scenario 2: Lock-down reduces infection rate by 30%
- Health system overload starting between May,8 and June,15
- 20,000 deaths reached during second week of June
- Peak overcome (health system capacities sufficient again) between late October and late January
- Pandemy runs out between late January and March (when, hopefully, vaccination will be available)
500.000-750.000 dead

Scenario 3a: Infection rate reduced to 1.25 by radical measures, e.g. curfews, factory closures
- Health system overload starting between mid-July and early August
- 20,000 deaths reached by early September
- Health System in overload until at least early May 2021 (but, hopefully, vaccination will be available earlier)
310.000-330.000 dead
Obviously economically and politically unfeasible - you can't almost completely curb down economic and social activities for a full year

Scenario 4: "Self-immunisation" of under 40s (plus mild lock-down for the remainder)
- Health system overload starting between May,13 and June,20
- 20,000 deaths reached quickly, already during the "self-immunisation" phase
- Peak overcome (health system capacities sufficient again) between early October and late December
- Pandemy runs out between late December and March (when, hopefully, vaccination will be available)
280.000-410.000 dead
 
A new study by the Italian Society of Environmental Medicine (Sima) suggests that the coronavirus could be transported via fine particles. They reported a strong correlation between the level of pollution with PM10 particles and the number of contamination 15 days later. The researchers also explain that the fine particles constitute a substrate which allows the virus to remain in the air under viable conditions for several hours or even several days, thereby increasing its contagiousness.

This confirms what I postulated on 5th March.
 
A new study by the Italian Society of Environmental Medicine (Sima) suggests that the coronavirus could be transported via fine particles. They reported a strong correlation between the level of pollution with PM10 particles and the number of contamination 15 days later. The researchers also explain that the fine particles constitute a substrate which allows the virus to remain in the air under viable conditions for several hours or even several days, thereby increasing its contagiousness.

This confirms what I postulated on 5th March.


This is so interesting! I think novel coronavirus teaches us many things - one about reducing air pollution, especially fine particle pollution caused by diesel car exhaust.
 
To make things even more complicated, COVID-19 has been mutating - and a person can get infected with two strains of coronavirus at the same time!
As one commentator put it - forget about COVID-19, there is already better version COVID-20 and perhaps COVID-20 PRO will be made available soon...

https://grapevine.is/news/2020/03/24/patient-infected-with-two-strains-of-covid-19-in-iceland/

"It’s been confirmed that an individual who tested positive for COVID-19 in Iceland has been infected by two strains of the virus simultaneously. The second strain is a mutation of the original novel coronavirus. It is thought that this could be the first recorded dual infection case of this kind.
Speaking to RÚV news yesterday, deCODE CEO, Kári Stefánsson confirmed the unusual infection. It is thought the mutated second strain could be more malicious or infectious because people infected by the dual-strain patient were only found to have the second strain. If this is the case, the virus could be mutating to become more infectious over time. However, Kári was unable to confirm this and suggested it could be a coincidence.
Kári also noted that the mutation found in the sample taken from this dually-infected patient is one that has not been found outside Iceland, according to international databases."

 
To make things even more complicated, COVID-19 has been mutating - and a person can get infected with two strains of coronavirus at the same time!
As one commentator put it - forget about COVID-19, there is already better version COVID-20 and perhaps COVID-20 PRO will be made available soon...

https://grapevine.is/news/2020/03/24/patient-infected-with-two-strains-of-covid-19-in-iceland/

"It’s been confirmed that an individual who tested positive for COVID-19 in Iceland has been infected by two strains of the virus simultaneously. The second strain is a mutation of the original novel coronavirus. It is thought that this could be the first recorded dual infection case of this kind.
Speaking to RÚV news yesterday, deCODE CEO, Kári Stefánsson confirmed the unusual infection. It is thought the mutated second strain could be more malicious or infectious because people infected by the dual-strain patient were only found to have the second strain. If this is the case, the virus could be mutating to become more infectious over time. However, Kári was unable to confirm this and suggested it could be a coincidence.
Kári also noted that the mutation found in the sample taken from this dually-infected patient is one that has not been found outside Iceland, according to international databases."

Is that the L and S strains of the virus? According to this article the more aggressive "L type" strain is responsible for 70% of infections in China. I couldn't find any information about the proportion in other countries though. It would be interesting to compare the fatality rate of the two strains too.
 
The article does not say it - only that the so called more aggressive (do they meant contagious?) strain has been found only in Iceland so far.

Otherwise there has been 40 (!!!!) COVID-19 strains analysed in Iceland.

"deCODE has uncovered from its analysis of the genetic sequences of 40 COVID-19 strains found in Iceland. According to Kári, the diversity of genetic sequences found in COVID-19 samples taken in Iceland indicate that the virus was brought to Iceland from a wider range of areas than was previously thought. The main origins of Icelandic infections are currently thought to be Italy, Austria, and Britain. A football match in the U.K. is thought to be the source for seven infections in Iceland."


 
The article does not say it - only that the so called more aggressive (do they meant contagious?) strain has been found only in Iceland so far.

Otherwise there has been 40 (!!!!) COVID-19 strains analysed in Iceland.

"deCODE has uncovered from its analysis of the genetic sequences of 40 COVID-19 strains found in Iceland. According to Kári, the diversity of genetic sequences found in COVID-19 samples taken in Iceland indicate that the virus was brought to Iceland from a wider range of areas than was previously thought. The main origins of Icelandic infections are currently thought to be Italy, Austria, and Britain. A football match in the U.K. is thought to be the source for seven infections in Iceland."



It's true that the article says "40 strains" but I think that they meant that they have identified 40 different mutations in all samples tested. A viral genome would need to accumulate enough nonsynonymous mutations to be reclassified as a different strain. I have read that so far over 150 mutations have been identified, enabling to follow the diffusion of the virus through its phylogeny, but the whole tree has only been divided into two strains.

I searched further and was able to find this phylogenetic tree of Covid-19 showing the various mutations and the two strains (if I am not mistaken the "S strain" is shown in green and the more virulent "L strain" is in yellow).

fig2_arXiv.jpg
 
Many oddities concerning this new Corona virus. One factor that seems to be more and more apparent as we observe this disease is that the more an individual spends around other infected people (like the brave doctors and nurses), the more serious their eventual complications tend to become. This is different than any other illnesses that I can think of off the top of my head.

I'm guessing this could be related to viral morphing resulting in some people picking up multiple strains at once.
 
Many oddities concerning this new Corona virus. One factor that seems to be more and more apparent as we observe this disease is that the more an individual spends around other infected people (like the brave doctors and nurses), the more serious their eventual complications tend to become. This is different than any other illnesses that I can think of off the top of my head.

I'm guessing this could be related to viral morphing resulting in some people picking up multiple strains at once.

Or it could be that some doctors are overworked, stressed, tired and therefore fall ill more easily.
 
It's true that the article says "40 strains" but I think that they meant that they have identified 40 different mutations in all samples tested. A viral genome would need to accumulate enough nonsynonymous mutations to be reclassified as a different strain. I have read that so far over 150 mutations have been identified, enabling to follow the diffusion of the virus through its phylogeny, but the whole tree has only been divided into two strains.

I searched further and was able to find this phylogenetic tree of Covid-19 showing the various mutations and the two strains (if I am not mistaken the "S strain" is shown in green and the more virulent "L strain" is in yellow).

View attachment 11900

Thanks for explanation, Maciamo! I was really puzzled about that multitude of strains in Iceland alone.

The important issue is response from the immune system -
I secretly hope that I've already developed immunity against COVID-19, but now the question is to what extent immunity from one strain can help in case of exposure to "later version" (another strain) of coronavirus.
I was reading earlier reports from Wuhan that about 14% of patients were readmitted again. The reason for readmission may be bacterial infection, which is rather typical, not the repeated infection with another strain of coronavirus, but it has not been clarified further.

Besides, the number of deaths in Italy is really way to high compared to many other countries. Many could suspect that Italian strain of coronavirus is somehow more deadly. Now the fatality rate is above 10% comparing all registered cases against deaths.
 
I was reading earlier reports from Wuhan that about 14% of patients were readmitted again. The reason for readmission may be bacterial infection, which is rather typical, not the repeated infection with another strain of coronavirus, but it has not been clarified further.

As you said, readmitted doesn't mean reinfected. It could just be a complication or opportunistic bacterial infection arising from a weakened immune system.

Besides, the number of deaths in Italy is really way to high compared to many other countries. Many could suspect that Italian strain of coronavirus is somehow more deadly. Now the fatality rate is above 10% comparing all registered cases against deaths.

Without proper statistics on the fatality rate by age group for each country it's hard to determine if the virus is really more aggressive in Italy. Northern Italy and central-northern Spain (Castilla y Leon + Madrid) have the oldest populations in Europe, so it's unsurprising to see more deaths there. Likewise, most of the Germans and Scandinavians infected were young and healthy skiers who could the virus while staying in the Alps, so their death rate should obviously be low.
 
Why is mortality from Covid-19 higher in Italy?

Besides, the number of deaths in Italy is really way to high compared to many other countries. Many could suspect that Italian strain of coronavirus is somehow more deadly. Now the fatality rate is above 10% comparing all registered cases against deaths.

I hope not as this strain has been exported to other countries too.
As not the whole population has been tested, and not everyone infected gets to a hospital, there is a difference between the real fatility rate and the appearant fatility rate.
 
I'm sipping a mixture of elderberry and echinacea.

Seem both immuun boosters and anti-viral.

I thought may be this is my 'placebo drink', but it seems not to be totally bogus against corona!

These results suggest that Echinaceapurpurea preparations, such as Echinaforce, could be effective as prophylactic treatment for all CoVs, including newly occurring strains, such as SARS-CoV-2.
https://www.researchsquare.com/article/rs-15282/v2

http://claudiacopeland.com/uploads/3/5/5/6/35560346/_hjno_elderflowers_abb.pdf
 
Interactive map of phylogency of Covid 19.

It also matters how many strains entered a country, and how early. Just click on country of choice and see the direction of the particular strain and then see the outflow.

https://nextstrain.org/ncov?d=tree&p=full&r=country

Am I reading this correctly?

Did one of the strains go from Shanghai to Belgium and then to Italy (bottom of chart)? Did another go to Italy from the UK?
 
According to The Economist, Covid-19’s death toll appears higher than official figures suggest. Analysing the data for northern Italy, central Spain and Alsace, they compared each region's normal death rate and the actual death rate in the past few weeks. When adding the officially reported deaths from Covid-19, there is still a major discrepancy in numbers. Apparently over half of additional deaths caused by Covid-19 are not reported!
 

This thread has been viewed 23265 times.

Back
Top