The Lemon Fool

sg31 wrote:

dealtn wrote:
This doesn't appear dissimilar to other episodes. There have been a number of people testing positive to antibody tests that had no idea they ever had it, and shared households with families and beds with partners throughout, but are the only one in that house to test positive. Yet some "super-spreader" events appear to give an impression it is easy to transmit.

How accurate are the antibody tests? I know some if not most can produce false positives by picking up earlier corona virus infections that weren't/aren't Sars- CoV- 2.

I ask because I'm not up to date on current antibody tests in use in this country.

It depends on the test but specificity is pretty good these days, close to 100%. Sensitivity can be more of an issue but over 95%.

John

redsturgeon wrote:It depends on the test but specificity is pretty good these days, close to 100%. Sensitivity can be more of an issue but over 95%.John

I'm not doubting you but could you please provide a reference for this? Only 3 weeks ago a company called Novacyt announced the launch of a new test which distinguishes between COVID-19 and other viruses:
https://www.investegate.co.uk/novacyt-s ... 00062644X/
implying that the test hitherto has been unreliable at identifying this particular virus.

langley59 wrote:

redsturgeon wrote:It depends on the test but specificity is pretty good these days, close to 100%. Sensitivity can be more of an issue but over 95%.John

I'm not doubting you but could you please provide a reference for this? Only 3 weeks ago a company called Novacyt announced the launch of a new test which distinguishes between COVID-19 and other viruses:
https://www.investegate.co.uk/novacyt-s ... 00062644X/
implying that the test hitherto has been unreliable at identifying this particular virus.

See https://thorax.bmj.com/content/early/2020/08/11/thoraxjnl-2020-215732

Clinical and laboratory evaluation of SARS-CoV-2 lateral flow assays for use in a national COVID-19 seroprevalence survey

Presentation is another area open for abuse.
I am disappointed by the ONS for presenting the deaths by age group graphically with a 'flexible' grouping along the bottom axis.
The under ones get a column (bizarrely), then the 1-14, then 15 to 44 (30 years), then 45 to 64 (twenty years), then65 to 74 (ten), then in tens thereafter.
It clearly weights the mass of deaths more evenly and not where it really is.
Subtle, but somebody, somewhere decided to do that.

W.

In the wider sense I think the government are trying to do what they think is best, but also popular. However, the politicians don't have the knowledge to select between the different scientific analyses so we end up in a mess.

johnhemming wrote:In the wider sense I think the government are trying to do what they think is best, but also popular. However, the politicians don't have the knowledge to select between the different scientific analyses so we end up in a mess.

I think it's far worse than that. Quite a few of us here spend considerable amounts of time learning about and keeping up with coronavirus and none of us here considers ourselves an expert. Politicians however are busy people with little time to learn stuff in depth yet they are making decisions based on what little they have picked up about COVID in between the press briefings, meeting constituents, taking conflicting expert advice and generally doing all the other stuff politicians have to do in a day. This I think is why they always seem to be three months behind the rest of us in absorbing each new piece of information that research reveals.

Give it another month or two and one of them might notice the mountain of circumstantial evidence that Vitamin D deficiency seems to be the reason BAME people are disproportionately susceptible to COVID-19, for example.

This article written by someone who appears to have the requisite background to judge claims that the false positive rate is enormous and consequently the government's published case figures are wildly exaggerated:
https://lockdownsceptics.org/lies-damne ... positives/

IMHO a huge problem is that the vast majority of MPs (and the civil service-media establishment) have an incredibly poor grasp of basic science and mathematics.

Consequently they don't have the toolkit to interpret data and to spot obvious errors, and are prone to being captured by plausible arguments which turn out to be seriously wrong.

A great example is false positives for coronavirus tests. The lockdown sceptics article gives a great example (below):

1,000 tests, 91 positives, test false positive rate of 0.8%. The politicians are seeing this as 91 positives with 0.8% x 91 false positives (i.e. less than 1 false) and are making policy on 91 positives (9.1%).

Yet the true number of expected false positives is 0.8% of 1,000 (the total number of tests) = 80 false positives. Thus there are only 11 actual positives (1.1%) which paints a very different picture. Policy in this case assumes a number of infections that is 8.3 times the actual number. Spectacularly wrong.

SalvorHardin wrote:
Yet the true number of expected false positives is 0.8% of 1,000 (the total number of tests) = 80 false positives. Thus there are only 11 actual positives (1.1%) which paints a very different picture. Policy in this case assumes a number of infections that is 8.3 times the actual number. Spectacularly wrong.

Don't follow that. 0.8% of 1000 is 8. Still a wrong result, but not as wrong as you state. Or have I made an error here?

malkymoo wrote:Don't follow that. 0.8% of 1000 is 8. Still a wrong result, but not as wrong as you state. Or have I made an error here?

My mistake. Missed off an extra 0 in the sample size, should have been 10,000. Doh!!! That will teach me to double check the figures.

Still works out as 91 positives vs 11 actual positives. The key thing being the huge discrepancy between these two figures.

Mike4 wrote:Give it another month or two and one of them might notice the mountain of circumstantial evidence that Vitamin D deficiency seems to be the reason BAME people are disproportionately susceptible to COVID-19, for example.

I think there is a general shortage of D (particularly D3), but I do suggest that my BAME friends take some vitamin D

However, I don't think that is the key issue. (I may be wrong).

johnhemming wrote:I think there is a general shortage of D (particularly D3), but I do suggest that my BAME friends take some vitamin D

However, I don't think that is the key issue. (I may be wrong).

I'd imagine that the key question for Vitamin D would be how many more African-Americans than whites are going down with Covid in the sunshine states where there ain't no such deficiency?

My understanding is that people of African descent have a whole raft of other genetic issues, ranging from sickle cell anaemia down to the inconvenient fact that black males (in the US) are up to twice as likely as whites to develop cancer or diabetes. Of course, some of that might be down to poor diet; but one in four will get prostate cancer - almost twice the rate for whites. And that's one place where the sun certainly don't shine.

Any or all of these things may be relevant factors when we're considering the body's natural resistance levels to an invader like Covid. Then again, it might all just be one gigantic coincidence? I'm inclined to think not. Our best hope of getting to the truth is to avoid the temptation to insist that we know it all, and that people who draw other inferences from us are decisively and definitively "wrong".

BJ

bungeejumper wrote:

johnhemming wrote:I think there is a general shortage of D (particularly D3), but I do suggest that my BAME friends take some vitamin D

However, I don't think that is the key issue. (I may be wrong).

I'd imagine that the key question for Vitamin D would be how many more African-Americans than whites are going down with Covid in the sunshine states where there ain't no such deficiency?

My understanding is that people of African descent have a whole raft of other genetic issues, ranging from sickle cell anaemia down to the inconvenient fact that black males (in the US) are up to twice as likely as whites to develop cancer or diabetes. Of course, some of that might be down to poor diet; but one in four will get prostate cancer - almost twice the rate for whites. And that's one place where the sun certainly don't shine.

Any or all of these things may be relevant factors when we're considering the body's natural resistance levels to an invader like Covid. Then again, it might all just be one gigantic coincidence? I'm inclined to think not. Our best hope of getting to the truth is to avoid the temptation to insist that we know it all, and that peop.le who draw other inferences from us are decisively and definitively "wrong".

BJ

And why is the death rate so high for African Americans but so low for sub Saharan Africa...except South Africa?

John

"More or Less" on BBC R4 has just covered testing and false positives and indeed false negatives; you may wish to listen via Sounds. It's a good programme.

johnhemming wrote:I think there is a general shortage of D (particularly D3)

I suspect most of us are more deficient in vitamin D than we think. I use an app on my phone 'dminder' which tracks how much time I spend in the sun and correlates this against my age, daily supplementation, location etc. to derive an estimated vitD level. I input that I take 1000iu of vitamin D3 as a supplement daily and throughout this glorious long summer (here in SE England) I have recorded my deliberate sun exposure, ie. sunbathing. For the record my skin is as tanned as its ever been, and I used to live/work in the West Indies and had a condominium on the beach (literally), and according to the app I'm at 41ng/ml of D3 which is just, I mean only just, in the green zone. I'm thinking of paying for a vitamin D3 blood test to see how accurate this app estimate is but, if its anywhere near accurate then given that I take a supplement and have sunbathed most sunny days all summer as much as is sensible without burning then most people are going to be seriously deficient.

You only need about 15 mins in the mid-day sun to get all the Vit D you need, as a general statistic, though as we know, the older you get, the less you absorb Vit D so one should allow for that. Of course, if you lather yourself with a powerful sun-screen before going into the sun, as we were warned to do in earlier years to avoid the risk of skin cancer, you won't be absorbing the vital sun rays. It's certainly worth having a test as it's dangerous to overdo it with supplements, bad for the bones I believe. You shouldn't need to take a supplement in the summer if it is sunny and you are exposing yourself to the sun around mid-day.

Shortage of Vit. D has a deleterious effect on the immune system which one would think would make you more susceptible to infection and various institutions have established that there is a connection between deficiency and lung and other diseases, including diabetes and MS. However, the jury is still out as to which is cause and which effect. A UK professor has concluded after research that it is the lung disease which causes the deficiency but I need to read all the papers before I am convinced.

Bouleversee wrote:"More or Less" on BBC R4 has just covered testing and false positives and indeed false negatives; you may wish to listen via Sounds. It's a good programme.

Unless I missed something, the Israeli Professor interviewed never actually made a comment about the possible magnitude of false positives in the tests performed. Only that the highly sensitive PCR test was indeed picking up viral material from people who were recovering from infection, and no longer infectious.

Nimrod103 wrote:

Bouleversee wrote:"More or Less" on BBC R4 has just covered testing and false positives and indeed false negatives; you may wish to listen via Sounds. It's a good programme.

Unless I missed something, the Israeli Professor interviewed never actually made a comment about the possible magnitude of false positives in the tests performed. Only that the highly sensitive PCR test was indeed picking up viral material from people who were recovering from infection, and no longer infectious.

I thought he said 1% false positives and rather more than that false negatives but would need to listen again to be sure as I was cooking at the time.

langley59 wrote:This article written by someone who appears to have the requisite background to judge claims that the false positive rate is enormous and consequently the government's published case figures are wildly exaggerated:
https://lockdownsceptics.org/lies-damne ... positives/

Could this be a site for an unbiased, impartial and accurate source of information

scotia wrote:Could this be a site for an unbiased, impartial and accurate source of information

Its certainly an alternative to the definitely biased, partial and inaccurate agenda pushing mainstream media in my honest opinion.