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How easy is it really to transmit Covid-19?(33 Posts)
The social distancing warnings about 2 metre , 1 metre or 1 metre plus drift on.
People have to go to work and yes children really should be going back to school for their overall health and wellbeing. But there still lurks that fear that maybe we will brush past someone who has 'it' and be struck down ourselves.
There are tales of catching the virus from surfaces as an infected person had previously touched it .There are animations showing people on the tube casting off Virus particles in all directions by not wearing a mask.
But what confuses me is that to find out if you have the virus you must subject yourself to an uncomfortable and often difficult test that ,because its uncomfortable and difficult ,has a high negative rate.
So if its so easy to cast off why is the test so hard to carry out?
This is a genuine query and one that has been bothering me for a couple of weeks now since a family member came down with flu like symptoms and had to be tested.
The swab test that they use for covid is similar to the one we use for flu; a swab of the throat and nostrils. The flu test is also not that reliable; just Googled it and 30 - 50% of people who actually have flu will get a negative result with a swab test:
Seems to be the same with covid, just Googled it and found a GP blog saying: "No test is 100% accurate. Although tests can perform well in ideal laboratory conditions, in real life lots of other factors affect accuracy including the timing of the test,
how the swab was taken,
the handling of the specimen."
(There are further links to research explaining how the above three factors can affect the reliability of a test result).
The test isn't physically difficult or particularly uncomfortable.
@sparepants dont agree. The throat swab made me gag and the sinus swab was uncomfortable- and I was doing it 10 weeks after the worst symptoms had passed (part of a research study), would have really struggled to get a good throat swab at all when I was in the coughing phase.
If it wasn't particularly uncomfortable for you then they probably didn't get far enough back in your throat to get a good sample.
Maintaining a two-metre distance from others is twice as effective at preventing the spread of coronavirus than a one-metre gap, a new study suggests.
Keeping one metre apart reduces the risk of transmission to 2.6%, while a two-metre gap decreases the chance of infection by a further 50% within the community.
According to the analysis published in The Lancet, modelling suggests for every extra metre further away up to three metres, the risk of infection or transmission may halve.
If an individual has Covid-19, standing within one metre of them results in a 13% chance of infection.
Not really a high infection rate tbh
There's an infectious dose and an amount that you need for testing to be successful.
If the infectious dose is low (just a few particles of virus maybe) then it's more transmissible. It seems this virus is highly transmissible, which is why you can catch it from surfaces and why we're still being told not to touch our faces (routes into the mucous membranes which will 'accept' the virus).
But the amount you need for testing might be much much higher - I don't know, just supposing. So they are trying to get into the places where the virus migrates to and replicates.
As for how hard is it to catch, I'm not sure. I have been working on a covid ward and have managed not to 'catch it' I think. But about half the staff have had symptoms or a positive swab test despite wearing PPE. We're being given antibody blood tests soon that are 100% effective apparently, so will be interesting to see if those of us who haven't had symptoms have actually had it at some point but just not shown symptoms.
I think wearing PPE must make a big difference to the risk of catching it and the viral load, even though we're only wearing surgical masks in most settings. 247 healthcare and care staff have sadly died so far, but seems that the majority of deaths were when we still weren't wearing PPE in all areas
cos Public Health England are stupid arseholes
But thats what I mean. You have to get really far back in a very specific place to 'catch' the virus sample you need to test.
So why, if its only in that place, is it deemed so easy to transmit to others?
You might have realised that Im not of a scientific bent but I do try to keep up with current trends but I really cant make out why its not possible to test in a less intrusive way.
Ive read that sewage from January has shown traces of the virus in Italy. So it is spread out throughout the body.
Surely a spit test would be as effective? Or blood test? Dont these bodily fluids carry just as much of the virus?
13% over what time period though? Is that 13% over 15min? An hour? When you hear stories about mass infections in church congregations or bars or from single meetings it makes you wonder. 1m and the infected person sneezes?
Doesn't really say. But time is certainly a factor. The tracking app will ask for people you were in contact with for more than 15 minutes
not the app, I mean the track and trace thing
You can not catch it if you brush past someone who has it
Covid is found in all bodily fluids apart from sweat.
Blood tests look for antibodies, which take a couple of weeks to develop after an infection, so aren't useful for diagnosing someone at the time.
Saliva/spit tests are being trialled atm:
I had a similar thought the other day. If we all have to wear masks to stop spreading it about them why can't we have a test that we just breathe on to get a result?
I get that there's a real answer to this and I'm not claiming to know better than the scientists developing the tests etc but it definitely crossed my mind!
I see your reasoning OP. If Covid can be transmitted on surfaces then presumably people must be carrying the virus on their skin or close to the surface of their body. (I’m quite happy to be corrected on any of this by the way, just seemed logical this would be the case).
Based on a sample of one I think the test is difficult to self-adminster efficiently. So any way of making it easier would make it more reliable.
It would have been coughed or sneezed onto the surfaces and then when you touch them and touch your face it is then transmitted through mouth, eye or nose. You arent secreting it out your pores
The test is uncomfortable. If it's not it's not done properly and about an inch from your ear. I have one every week at work.
I think that's a good question. Maybe the thresholds are just really different for the two situations? If sitting at a table eating a meal with someone for an hour gives you a 10% chance of contracting a potentially-fatal disease, that seems like a pretty high risk. But a test you breath on that has only a 10% chance of correctly spotting that you were a carrier sounds pretty ineffective.
With an individual test you want to be as certain as possible that if someone is infected then that will definitely show up.
There are collective tests that do work much less intrusively though, like those testing town sewers to track presence of infection.
Teenage DS had a test in hospital and the doctor administering it said that if it doesn't make you gag (when they do the throat) or your eyes water (when they do the nose) then it's probably not been administered far enough.
Let's hope the saliva tests are developed quickly and are reliable
I don't understand why people say it has to be coughed or sneezed onto a surface. How often, recently, have you seen someone cough or sneeze? How often have you coughed or sneezed yourself?
Surely if it is transmitted via surfaces then just breathing on them has to be enough?
Test made me gag and I never thought I had it, was one of the studies going on. I'm concerned by the high false negative rate which would mean a fair number if people that do have it being sent back to school/work etc. You're pretty much ok if you're outside but sat in an enclosed space with people means your much more likely to pass it/ get it
It is the test that is unreliable due to the substrate, easy death of the virus, contamination etc. Not that it isn't easy to swab for the virus and catch it on the swab - it is. It's once it is on the swab that the issue occurs.
COVID is harder to catch than your usual cold, but easier than some others. This is due to how much is present within bodily fluids and it's life span on various surfaces. Obviously you are more likely to catch it the more you come into contact with it and the time frame of touching something that has the virus on it. So things like tills, keyboards, touch screens etc are high risk.
My dad was the only person in the house with mum for the 2 weeks prior to her going to hospital and dying 2 days later from Covid. He was her sole carer as she had health issues that masked the symptoms of the bug. He spent the last night at home with her holding her hand for hours as well as all the other contact he'd had with her. He has not had any symptoms before or since in the 11 weeks since mum's death. We believe mum caught it at hospital during one of her radiotherapy treatments. Why dad didn't contract it remains a mystery.
There was a scientific article which said they took some samples from 2016 before covid and found that 40% of those samples were immune to covid . They think that some people have immune cells which wipe it out . My hubby had it and I work in the frontline I was negative antibody test . Didn’t have it never had it
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