Who Are The Infected?

RossyG said:

I read a couple of days ago in an article (no link, alas) that actually just one metre is considered sufficient. Perhaps they suggested two metres to make doubly sure, if that’s the case.
i.

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CheeseRolls said:

Now that we have testing numbers up to a significant level, I think this becomes a really important question.

Up until now I think many people have been quite dismissive of the numbers of people testing positive. As a trend measure it isn't particularly helpful, given how few people were previously tested. However if after lock down we have 4000 people infected, we need to have a picture of who these people are and how they came to be infected. I am not proposing plague markers on front doors, just some basic anonymised information on geography, employment, contact, age, sex, pre-existing health conditions.

We need to see a picture emerge that will either confirm or dispel some of the anecdotal stories such as;

Young children can not catch/spread the virus?
Asthmatics need to be highly protected (do hospital admissions support this?)
Smokers are/are not more likely to be admitted to hospital with infection?
You can catch the virus from sitting on a toilet seat ?(sorry to be flippant, but how important is 2m distancing outside, what works/doesn't work indoors)
Do otherwise healthy over 70s really need to isolate?
Is it mainly fat old blokes admitted into hospital?

Debate away, but please also add evidence from here or elsewhere in the world, which can inform the discussion. If it descends into another who wants to end isolation more/accusations of people enjoying being furloughed thread - mods please merge it.

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CheeseRolls said:

Now that we have testing numbers up to a significant level, I think this becomes a really important question.

Up until now I think many people have been quite dismissive of the numbers of people testing positive. As a trend measure it isn't particularly helpful, given how few people were previously tested. However if after lock down we have 4000 people infected, we need to have a picture of who these people are and how they came to be infected. I am not proposing plague markers on front doors, just some basic anonymised information on geography, employment, contact, age, sex, pre-existing health conditions.

We need to see a picture emerge that will either confirm or dispel some of the anecdotal stories such as;

Young children can not catch/spread the virus?
Asthmatics need to be highly protected (do hospital admissions support this?)
Smokers are/are not more likely to be admitted to hospital with infection?
You can catch the virus from sitting on a toilet seat ?(sorry to be flippant, but how important is 2m distancing outside, what works/doesn't work indoors)
Do otherwise healthy over 70s really need to isolate?
Is it mainly fat old blokes admitted into hospital?

Debate away, but please also add evidence from here or elsewhere in the world, which can inform the discussion. If it descends into another who wants to end isolation more/accusations of people enjoying being furloughed thread - mods please merge it.

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CheeseRolls said:

This is the sort of study we need a lot more of right now. There are some really interesting patterns highlighted here. If we can get a whole load more of these types of rigorous studies, a real pattern will start to emerge as to who gets infected and how. The infection rates within households really surprised me, I thought the rates would be much higher. Other highlights were 20% asymptomatic and infection rates 10 times higher than reported.

https://www.uni-bonn.de/news/111-2020

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Harry Wilson's tackle said:

The study reports that 20% of those infected are asymptomatic. That's stunning. Well, given that this is a random sample of a population (a good thing from a design and reliability perspective), that number does not fit with the narrative that the vast majority of those who have been infected in the UK are (or were) asymptomatic.

Also, if you remember the early quotes that in the UK 40 million people need to have the disease for herd immunity to be reached (this is a reliable estimate based on several decades' worth of viral epidemiology), with only 20% of cases asymptomatic this means we need to have 32 million symptomatic sick people in the UK to obtain herd immunity (80% of the 40 million, with the other 8 million = 20% asymptomatic). Or we need to immunize way more than 40 million with a vaccine (if we can make one that works).

If people who think the UK hospital death data accurately reflects the national trend (a steady fall in deaths) which it may (I'm not sure, but it may) this means we need to understand the reason. It can't be herd immunity. It isn't vaccination. Could it be social distancing? If it is we will need to social distance till the 40 million is reached....could be decades. If not social distancing then.....this must be a seasonal virus after all. That's my big hope.

Apologies for the inevitable flaws in my reasoning.

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Harry Wilson's tackle said:

The study reports that 20% of those infected are asymptomatic. That's stunning. Well, given that this is a random sample of a population (a good thing from a design and reliability perspective), that number does not fit with the narrative that the vast majority of those who have been infected in the UK are (or were) asymptomatic.

Also, if you remember the early quotes that in the UK 40 million people need to have the disease for herd immunity to be reached (this is a reliable estimate based on several decades' worth of viral epidemiology), with only 20% of cases asymptomatic this means we need to have 32 million symptomatic sick people in the UK to obtain herd immunity (80% of the 40 million, with the other 8 million = 20% asymptomatic). Or we need to immunize way more than 40 million with a vaccine (if we can make one that works).

If people who think the UK hospital death data accurately reflects the national trend (a steady fall in deaths) which it may (I'm not sure, but it may) this means we need to understand the reason. It can't be herd immunity. It isn't vaccination. Could it be social distancing? If it is we will need to social distance till the 40 million is reached....could be decades. If not social distancing then.....this must be a seasonal virus after all. That's my big hope.

Apologies for the inevitable flaws in my reasoning.

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Guinness Boy said:

Apology accepted

No, seriously. we wouldn't need to vaccinate 40 MILLION people would we? We'd need to identify the most at risk people who hadn't already had it, keep R less than one and contact / trace anyone who tests positive. That's a lot less bleak.

For example, the BCG I had (and I suspect you may have) that was so much fun to punch / have punched is no longer given. That doesn't mean 40 million people in the UK have had TB.

Or is it my logic that's flawed?

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RossyG said:

I read a couple of days ago in an article (no link, alas) that actually just one metre is considered sufficient. Perhaps they suggested two metres to make doubly sure, if that’s the case.

Click to expand...

Guinness Boy said:

Apology accepted

No, seriously. we wouldn't need to vaccinate 40 MILLION people would we? We'd need to identify the most at risk people who hadn't already had it, keep R less than one and contact / trace anyone who tests positive. That's a lot less bleak.

For example, the BCG I had (and I suspect you may have) that was so much fun to punch / have punched is no longer given. That doesn't mean 40 million people in the UK have had TB.

Or is it my logic that's flawed?

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dazzer6666 said:

I interpreted that a bit differently (I may be wrong) - the 20% asymptomatic must have had it at the time they were tested - it doesn't cover those that might have already had it without realising ?

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Harry Wilson's tackle said:

OK, good point. It says "“Apparently one in five infections occurs without noticeable symptoms suggests that infected persons who secrete virus and can infect others cannot be reliably identified on the basis of recognizable symptoms of the disease,". However, what it doesn't say is how many of those found to be infected, as defined by the test, went on to develop the disease after they had been tested.

Let's imagine it is none. This means that my stark assessment is correct. Let's imagine it is all of them./ This means that everyone tested positve either has had or is just about to get sick. That's even worse than I thought.

Digging deeper, they did two tests over several weeks: "“By combining PCR and ELSIA tests we are able to detect acute as well as elapsed infections,” says Prof. Hartmann. Preliminary studies showed that the ELISA test is false positive in about one percent of the cases. “However, with such high frequency of infections in Gangelt, a one percent false positive rate is not critical". By this I suspect that the 20% are people who tested positive and some weeks later still hadn't expressed symptoms.

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CheeseRolls said:

There is another way of looking at the same problem, which is to take the extrapolated mortality rate, which was 0.37%. If you were to apply that to a population of 80 million that is the equivalent of 296,000 deaths. That doesn't tell the whole story, I am imaging an infection model, much like bumper cars.

If you have 3 cars out and in the first head on collision the fat bloke smashes the skinny teenager due to weight advantage, you can imagine a scenario where the other two cars are happy to bump, but spend all their time dodging the fat bloke.

If you add more cars, you will get more collisions and spotting the fat bloke coming will be harder. This holds up to the point when there are too many cars on the rink (is that what you call these things?) at which point everything grinds to a halt because no one can move.

Now imagine somehow the ride owners can magically increase the size of the rink, to whatever size they want. All of a sudden it becomes very difficult to predict the number of collisions.

This study was great, in that it was sparked by a specific event (carnival) and then contained by isolation. This might explain why only 15% got infected. How whole households weren't infected is much harder to understand and or explain.

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Harry Wilson's tackle said:

Nail. Head.

At every turn, with every bit of new data and every study there are questions that are hard to answer. It concerns me that so often when a few bits of data point to a testable prediction it turns out the pridiction isn't correct. I'm glad I don't work in epidemiology. If I did, you would know me by the trail of the dead. (That is almost an actual name of a band but I'll refrain from posting a youtube clip....for now, anyway )

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CheeseRolls said:

As well as trying to dodge the infection, I am also trying to stay away from the absolutists on here, who can only deal in certainties. The correct answer to you are wrong, is yes and so is everyone else. The best outcome is to be the least wrong you possibly could and accept that you will never be able to prove it to the satisfaction of anyone else.

It is mind boggling to think that this crazy unpredictable virus of Chinese origin, will somehow be constrained by the ultimate piece of European bureaucracy that is the metric system. We just have to agree if it is a 1 metre or 2 metre distance beyond which the virus is unable to travel.

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