What I don't understand about Covid19

[Roobarb]

I'm putting this on as a separate topic so that it doesn't get lost amongst the other discussion and in the hope that someone with the appropriate sort of knowledge can shed some light on it for me.

Let me start by saying that I have the utmost respect and admiration for the scientists and medical people who are providing information on this virus.

The thing that I don't understand is how we don't have a definitive answer as to how long the virus is active on surfaces. I ignore any of the stuff that's circulated on lots of websites as the majority is untrustworthy. The government and NHS websites don't have the information and the WHO website says this:

It is not certain how long the virus that causes COVID-19 survives on surfaces, but it seems to behave like other coronaviruses. Studies suggest that coronaviruses (including preliminary information on the COVID-19 virus) may persist on surfaces for a few hours or up to several days. This may vary under different conditions (e.g. type of surface, temperature or humidity of the environment).

My question is this - During all the research that's gone into this, how is it that the scientists haven't yet found out? I know this is a simplistic view and there obviously are reasons but isn't it a case of putting the virus on various surfaces in a controlled environment and seeing how long it lasts? I don't expect them to conduct such research just to satisfy the curiosity of people like me, I thought it would be useful in identifying how and where the spread of it happens.

Do we have any Rootschatters who are retired scientists or the like who can provide some insight into this? Feel free to shoot me down in flames for my simplistic view. 

[Mike in Cumbria]

Yes, it has been researched.

https://www.forbes.com/sites/ericmack/2020/03/15/new-coronavirus-study-shows-how-long-hcov-19-can-live-on-different-surfaces/#1c808270412f

[Mike in Cumbria]

Here's the research referred to in that article.

https://www.medrxiv.org/content/10.1101/2020.03.09.20033217v2

[GrahamSimons]

Biologist here.
I think the issue is - it all depends!
There are a wide variety of surfaces - and you'd need to test many of them. For instance, some metals have a degree of antiviral activity; some are more absorbent than others; some will come into contact with people more.
Detecting the viral proteins and RNA is one thing - that's (relatively) easy. However to know whether these components come from viable virus particles is another - that would almost certainly mean investigating their infectivity. That wouldn't be a particularly safe trial on human subjects; it might be possible on other targets which could be (I don't know the detail here) tissue culture (reported in the non-peer-reviewed paper cited above) or mice.
So... need multiple tests on multiple materials. Need to test infectivity. It's likely that environmental conditions would also be important - moisture, temperature, lighting (particularly UV, I'd expect)

[Albufera32]

I'm not a scientist, but I am a science teacher. One of the first things we teach in schools is the concept of the "fair test" - ie that you can only really rely on any experimental result if you make sure to only change 1 variable. In order to do that, you need to control all the other possible variables. (What you refer to as a controlled environment.)

The problem is, to control ALL possible variables, you first have to figure out WHAT all the variables are, which is the tricky part. Some are obvious, such as temperature, others less obvious, and some may or may not actually have any effect (eg in this case, the smoothness of the surface, the density of the material, how porous the material is) and all of those variables may be slightly different for each and every virus.

On top of that, you have to actually isolate the specific virus in the first place.

Or to cut a long story short, the simplest answer to your question is because it is a lot more complicated than it seems.

[Roobarb]

Many thanks for the replies. I've been so frustrated at reading so many differing reports, it's hardly surprising that they differ widely when there are so many variables.

Science was never my strong point, I do admire people like yourselves. 

[Roobarb]

May I ask another scientific question? The background to my question is a little bit lengthy so bear with me......

I haven't been anywhere near another person for two weeks, more than the statutory distance has been maintained with the very few people I have seen. I have no symptoms and am generally quite fit but as I'm asthmatic I'm being ultra cautious. I live alone and no-one has been nearer than the outside of the letterbox.

Every day I go for a walk on the very large field that's a very short distance from my house, it's used as a playing field, dog walking area and general green space recreation area. There are only usually a handful of people on the field when I go there and I stay a long way away from them (I have had a couple of four legged friends coming to greet me,  I make cooing noises to them but haven't touched them). The field leads to a strip of woodland and I use the path through there, veering back onto the field if I see anyone coming towards me.

When I get home I leave my jacket and shoes in my very small hallway, then I wash my hands, wipe down the door handles, my gloves if I've worn them and even my front door key. When any junk mail leaflets or non urgent post is delivered I leave it there for a few days before dealing with it. Yes, my hallway is getting untidy!

Am I being over cautious? I haven't touched anyone or anything while I've been out or been anywhere near them. I know a lot is still unknown about Covid19 but I think it's been said that it does behave in some ways like other viruses. I'm aware that one of the main ways of it being spread is by coughs and sneezes but is it airborne in any other way?

Would be grateful for observations from the scientists. 

[Christine53]

I'm not a scientist , far from it , but if you haven't touched anything at all while you're out then you probably are being a tad over cautious. However if it makes you feel better doing it then where's the harm.  As far as post and other deliveries are concerned I do leave things on one side before dealing with them - that's me being cautious and feeling better for it as a result. ( there does seem to be a bit of doubt about how long the virus survives on paper and cardboard ).

[Mike in Cumbria]

Sounds like a good set of habits that will keep you as safe as possible.
Why worry about being over-cautious?