Virus lifespan on surfaces and in air explained

[JohnD]

were you able, from watching his video, to answer the two question I asked?

 

[ReJect]

were you able, from watching his video, to answer the two question I asked?

No. I just took from it that this virus can potentially survive fairly long periods from test results.
Particularly the airborne risk I noted.
Really though all I need to know at present.
Keeping myself isolated

 

[IT Minion]

- I have a room that one or more other people were in earlier. One or more of them might or might not have been infected with CV. If I go into the room, will I catch it?

- Without saying how big the room is, or how it is ventilated, how long will it be before it is safe?

No one can answer that question absolutely. Give it a year and there'll be enough data to give a good guess.

Question 1: theoretically impossible to answer with yes or no. If we knew one of the people in the room was infected then it might be possible to work out if you had enough data.

Question 2: give it three days and you're going to be fine unless you start licking every square centimetre.

 

[Munroast]

No one can answer that question absolutely. Give it a year and there'll be enough data to give a good guess.

Question 1: theoretically impossible to answer with yes or no. If we knew one of the people in the room was infected then it might be possible to work out if you had enough data.

Question 2: give it three days and you're going to be fine unless you start licking every square centimetre.

from the video the air should be completely safe to breath after 3 hours.
however if it was a very large room and only one ccv sufferer was only in for a short time, then the chance would be pretty slim.

 

[EFLImpudence]

Read it yourself and see if you can use it to answer the following real-life questions:

were you able, from watching his video, to answer the two question I asked?

Are you meaning the video or the article?

- I have a room that one or more other people were in earlier. One or more of them might or might not have been infected with CV. If I go into the room, will I catch it?

As I said - possibly.

- Without saying how big the room is, or how it is ventilated, how long will it be before it is safe?

Not possible to say other than until the maximum time the virus can survive which is not stated.

 

[JohnD]

Are you meaning the video or the article?

When I said "from watching his video?"
I meant the video.

But I read the source document several days ago, and I couldn't see that it helped with real-life applicability, such as those questions. I didn't find it useful. Did you find it had applicability?

I didn't watch the whole video.

 

[EFLImpudence]

Ok.

Then the answer to both is - no.

 

[Notch7]

I thought the video was pretty useful. Its an overall insight, I dont think we can read too much into the specific numbers.

The way I see it, the risk from a virus on a hard surface is pretty low to negligable after 72hours.

And the virus contained in droplets can be active upto 3 hours in the air.-by its very nature, the time cant be very accurate, but it gives us a factor. Its clearly not seconds nor 3 years, but lets say it could be an hour or 8 hours.
The fact it may be airborne for any time is useful to know.

I thought a key point was that Covid / SARS 2 is a virus that is in the upper respiratory tract. An infected person can emit a high viral load with no symtoms

 

[IT Minion]

I don't think that Viral load means what people think it means.

It's a term mostly used in HIV/AiDS where the amount of the virus in your blood is higher or lower. Lower amounts of it tends to mean fewer symptoms, normally achieved thanks to medication.

If that is the technical use of the term then saying someone is exposed to a high viral load is ******. Like saying that you need to apply to your council for building control permission.

 

[motorbiking]

The volume might not be but the number is.


Ok. so if you start with twice as many, that will take an extra time period.


Then half-life is irrelevant.


so, the 72 hours is irrelevant.


I don't follow. If people have a life expectancy of 80 years then there is no half-life.
Some will last longer and some - not half - shorter.


Therefore they might all last one day - or three days (72 hours) as is being stated - and then what?

No each cell is exposed to the same statistical probability of dying within a minute or 10 days.
The half life shows us how to create a realistic model based on a sample of a statistically relevant amount and how long it took for half to die.

The people thing is a good analogy.

If life expectancy is 80 years and you have a sample of 50 and a sample of 500 will the sample of 500 take longer to die than the sample of 50?
Each person in the sample has the same risk of dying at 1 or 81. All other things being equal.

On a completely separate note there has been some criticism of the aerosol test arguing that a medical nebuliser is not a realistic equivalent to a sneeze of cough as its designed to atomise a liquid into the air.

 

[Brigadier]

I don't think that Viral load means what people think it means.

It's a term mostly used in HIV/AiDS where the amount of the virus in your blood is higher or lower. Lower amounts of it tends to mean fewer symptoms, normally achieved thanks to medication.

If that is the technical use of the term then saying someone is exposed to a high viral load is ******. Like saying that you need to apply to your council for building control permission.

With regard to CV, viral load means :

- high viral load ; for the sufferer, very infectious to others. But, not necessarily displaying symptoms ("super spreaders")
- high viral load ; for the health care person, to be exposed to a high vital load, potentially very bad. The immune system needs time to fight off a pathogen; ok if the pathogens are introduced at a low and manageable level, not so if they arrive in a tsunami.

 

[JohnD]

Interesting article, includes how long (or indeed, short) a time an infected person is spreading a virus.

And a passing comment about Swine Flu at Eton.

https://www.cambridgeindependent.co...we-know-and-dont-know-about-covid-19-9104220/

 

[EddieM]

No each cell is exposed to the same statistical probability of dying within a minute or 10 days.
The half life shows us how to create a realistic model based on a sample of a statistically relevant amount and how long it took for half to die.

The people thing is a good analogy.

If life expectancy is 80 years and you have a sample of 50 and a sample of 500 will the sample of 500 take longer to die than the sample of 50?
Each person in the sample has the same risk of dying at 1 or 81. All other things being equal.

On a completely separate note there has been some criticism of the aerosol test arguing that a medical nebuliser is not a realistic equivalent to a sneeze of cough as its designed to atomise a liquid into the air.

As before viruses have no cells, they are much simpler than that.

Anyway, I applaud all the amateur virologists and epidemiologists in the forum. Might want to throw in the mathematicians into the mix too.

 

[IT Minion]

With regard to CV, viral load means :

- high viral load ; for the sufferer, very infectious to others. But, not necessarily displaying symptoms ("super spreaders")

No arguments on that part.

- high viral load ; for the health care person, to be exposed to a high vital load, potentially very bad. The immune system needs time to fight off a pathogen; ok if the pathogens are introduced at a low and manageable level, not so if they arrive in a tsunami.

This bit not so much. Its probably true but I'm pretty sure it isn't 'Viral load'.

 

[EFLImpudence]

No each cell is exposed to the same statistical probability of dying within a minute or 10 days.

It is not. It appears to be dependent on the landing surface for one thing.
If you accept the maximum is 10 days then that contradicts the 72 hours or half life of 6 hours and must leave many more alive after that 72 hours.

The half life shows us how to create a realistic model based on a sample of a statistically relevant amount and how long it took for half to die.

Not really. It depends how many there are at the start (and where they land).

The people thing is a good analogy.

No, it isn't. The life expectancy is the average; not a half-life.

If life expectancy is 80 years and you have a sample of 50 and a sample of 500 will the sample of 500 take longer to die than the sample of 50?

No, but it is not to do with half-life but the maximum life.
Of course it would take longer if it were to do with half-life.

Let's take the fifty people and a half-life of 25; it can't be much higher with the maximum life possible (maybe a little over 100 for a very few).
If 25 die at 25; 13(can't have half a person) at 50; 7 at 75 and 5 at 100(supposed maximum) - then the average (LE) would be only 46.
If you start with 100 then there will be twice as many alive between 75 and 100 but the average will be the same 46.

Each person in the sample has the same risk of dying at 1 or 81. All other things being equal.

Yes, but when LE is 80, only so many can die young with the maximum age being what it is.