Covid on surfaces

[Arizona11]

Please excuse my ignorance. Many articles on the web advise how long COVID lasts on different surfaces.

What happens then? Does the virus disintegrate or what? What physically happens to it so that the surface becomes safe? Specific answers would be appreciated.

Many thanks.

[csearle]

Please excuse my ignorance. Many articles on the web advise how long COVID lasts on different surfaces.

What happens then? Does the virus disintegrate or what? What physically happens to it so that the surface becomes safe? Specific answers would be appreciated.

Many thanks.

My limited understanding is that the virus becomes unviable i.e. wrecked (from its perspective). So for example if it lands on copper I have heard on the radio that chemical interactions make the virus unviable quicker than when it lands on plastic.

Chris
(I'm an electrician not a virologist so please use a pinch of salt.)

[Midsmartin]

I would hazard a guess that the virus coat, including the spike protein, breaks down when dried out, or reconfigures itself into a form that's inactive. Perhaps the protein shell only remains intact in water, or fluid with a similar salt concentration to cytoplasm. These proteins have evolved to adopt a certain configuration when they are put together inside the liquid of a cell. They probably don't survive dehydration well.

[GrahamPlatt]

Proteins “denature” in adverse circumstances - so think of egg white when heated; the 3D structure (which is necessary to their proper operation) becomes deranged.

http://chemistry.elmhurst.edu/vchembook ... ation.html

As I understand it, the SARS virus on a neutral surface at room temperature can remain “viable” for several days.
I’m not sure whether dehydration plays a part.

[Dod101]

I have read recently that the need for all the spraying of tables, chairs, supermarket trolleys and so on has now been thoroughly debunked but I am no denier and still wash my hands and so on after being out and about. In fact, observing the work that goes on in a local restaurant where I was on Sunday it is fairly cursory anyway, but as I was eating outside i did not have any concerns.

What does concern me though is that all the extra work being done is leaving us exposed to a lot of other bugs since we are not getting the chance to build our natural immunity for the winter.

Dod

[Alaric]

I have read recently that the need for all the spraying of tables, chairs, supermarket trolleys and so on has now been thoroughly debunked

It would be nice to know where this appeared. This affects board and card games as well. At some stage, chess players were expected to use two sets and boards to avoid both players handling the same pieces. It was like the rules for playing visually handicapped players where you and the opponent have to announce their moves.

[Hallucigenia]

I have read recently that the need for all the spraying of tables, chairs, supermarket trolleys and so on has now been thoroughly debunked

It's not that black and white - "debunked" is the wrong word. You can get it from contact but it accounts for <5% of transmission - aerosols are the main thing to worry about, from crowds, close contact and confined spaces. Imagine you're trying to avoid cigarette smoke. But washing hands is still a good idea when you've been out, particularly if you're touching things like lift buttons and card payment pads that a lot of other people will touch.

I'm not sure the OP will be able to find specific research on how it denatures - people tend to be more interested in whether it is still infectious or not and that's that, it's a bit like investigating the actual cause when someone dies of "old age", everything gets a bit knackered at the same time.

But broadly, if you imagine that a virus is like a DVD inside a soap bubble, with the DVD carrying instructions on how to make more virus. It stops working if the soap bubble pops, dries out to form a scum, or something goes wrong with the DVD - scratches, a crack, delamination etc. Except that gives the wrong idea of the durability of these things - the outer membrane is rather tougher than a soap bubble, and RNA is far less robust than a DVD. It just falls apart at room temperature, particularly if there's any UV light around - it's a terrible chemical for storing your genome long-term, but has advantages when it comes to hijacking the host's replication machinery. So very time the virus is coughed out, it's in a race against time to find a new host before its RNA falls apart as it has a typical half-life measured in hours, all it can do is produce billions of virus particles and hope that it finds another host within a day or so out of the body.

[Dod101]

I will try to find the source. It was in a newspaper which I may have thrown out.

Meanwhile, with great respect to those who write with some authority, it would be good to know if these are professionals, simply well informed amateurs, or just making it up (which I am sure would never happen on this site!) I have actually thought this thought quite a bit when reading some of the many posts re Covid.

Dod

[Hallucigenia]

I will try to find the source. It was in a newspaper which I may have thrown out.

Whilst the newspapers have not done too badly, there's plenty of better sources for this kind of thing, for instance this Nature article from January gives a pretty good overview (and specifically mentions some research on eg poker playing, which found no threat from rhinovirus on chips/cards)

https://www.nature.com/articles/d41586-021-00251-4

Also current WHO and CDC advice :
https://www.cdc.gov/coronavirus/2019-nc ... ssion.html
"the relative risk of fomite transmission of SARS-CoV-2 is considered low compared with direct contact, droplet transmission, or airborne transmission...the risk of SARS-CoV-2 infection via the fomite transmission route is low, and generally less than 1 in 10,000, which means that each contact with a contaminated surface has less than a 1 in 10,000 chance of causing an infection"

https://www.who.int/news-room/q-a-detai ... ransmitted
" Current evidence suggests that the virus spreads mainly between people who are in close contact with each other, typically within 1 metre (short-range). A person can be infected when aerosols or droplets containing the virus are inhaled or come directly into contact with the eyes, nose, or mouth.
The virus can also spread in poorly ventilated and/or crowded indoor settings, where people tend to spend longer periods of time. This is because aerosols remain suspended in the air or travel farther than 1 metre (long-range)."

[Lootman]

I have read recently that the need for all the spraying of tables, chairs, supermarket trolleys and so on has now been thoroughly debunked

It would be nice to know where this appeared. This affects board and card games as well. At some stage, chess players were expected to use two sets and boards to avoid both players handling the same pieces. It was like the rules for playing visually handicapped players where you and the opponent have to announce their moves.

In chess you generally only touch your own pieces, except for when you capture an opponent's piece, which could be solved by the other player removing his own piece once he sees your move. They also touch different buttons on a chess clock. The bigger risk would be sitting across from your opponent just a few feet away, facing each other, for several hours.

More generally I doubt that it spreads much by surfaces since in that event the spread would be much more random, since it would be so hard to avoid contact with things that other people have touched recently.