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Deep Dive!
This is an important thread about testing for SARS-CoV-2 which will explain:
-why herd immunity is possible at 10-20%
-why testing has really let us down and led to bad policy decisions
I will talk about two types of testing:
-PCR testing
-AB testing
First PCR:
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This is an important thread about testing for SARS-CoV-2 which will explain:
-why herd immunity is possible at 10-20%
-why testing has really let us down and led to bad policy decisions
I will talk about two types of testing:
-PCR testing
-AB testing
First PCR:
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PCR can make billions of copies of a specific DNA/RNA sample (RT-PCR used for Covid because it’s an RNA virus)
It is run in cycles with the amount of RNA increasing during each cycle
If you run enough cycles you can take a very small amount of RNA and make it very large
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It is run in cycles with the amount of RNA increasing during each cycle
If you run enough cycles you can take a very small amount of RNA and make it very large
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Some definitions:
Sensitivity - how many false negatives you get
Specificity - how many false positives you get
Earlier there was talk of PCR with a sensitivity as low as 66%
That is no longer the case, most are over 95% sensitivity and many at 100%
3 https://www.finddx.org/covid-19/sarscov2-eval-molecular/molecular-eval-results/
Sensitivity - how many false negatives you get
Specificity - how many false positives you get
Earlier there was talk of PCR with a sensitivity as low as 66%
That is no longer the case, most are over 95% sensitivity and many at 100%
3 https://www.finddx.org/covid-19/sarscov2-eval-molecular/molecular-eval-results/
To ensure a high sensitivity, manufacturers recommend Ct as high as 40
Ct (cycle threshold) is how many cycles are necessary to get a result
They made these tests super accurate for finding infected
What they never considered is that “infected” are not a homogenous group
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Ct (cycle threshold) is how many cycles are necessary to get a result
They made these tests super accurate for finding infected
What they never considered is that “infected” are not a homogenous group
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A problem emerges when we see what the number of cycles actually means
38-40 means you are picking up scant amounts of RNA or environmental contaminants
So you’re going to detect any amount of SARS-CoV-2 RNA, but doctors don’t know the Ct, they just see positive/negative
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38-40 means you are picking up scant amounts of RNA or environmental contaminants
So you’re going to detect any amount of SARS-CoV-2 RNA, but doctors don’t know the Ct, they just see positive/negative
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As the NYT reported in an article you’ve probably read:
“up to 90 percent of people testing positive carried barely any virus”
Most correctly interpet this as evidence of the “Casedemic” being used to keep schools closed - because it is!
6 https://www.nytimes.com/2020/08/29/health/coronavirus-testing.html
“up to 90 percent of people testing positive carried barely any virus”
Most correctly interpet this as evidence of the “Casedemic” being used to keep schools closed - because it is!
6 https://www.nytimes.com/2020/08/29/health/coronavirus-testing.html
But what I see is 90% asymptomatic cases!
Dead viral shedding occurs long after infection so PCR can actually be used to confirm that a large number of people are asymptomatic
You may argue, low viral RNA doesn’t necessarily mean they are asymptomatic
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Dead viral shedding occurs long after infection so PCR can actually be used to confirm that a large number of people are asymptomatic
You may argue, low viral RNA doesn’t necessarily mean they are asymptomatic
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But there’s lots of proof that they are
96% of PCR confirmed cases in this prison study were asymptomatic
I also got a message from a midwest plant manager telling me that of 10k tested, 1/3 tested positive, 95% of the positive cases were asymptomatic
8 https://www.reuters.com/article/us-health-coronavirus-prisons-testing-in-idUSKCN2270RX
96% of PCR confirmed cases in this prison study were asymptomatic
I also got a message from a midwest plant manager telling me that of 10k tested, 1/3 tested positive, 95% of the positive cases were asymptomatic
8 https://www.reuters.com/article/us-health-coronavirus-prisons-testing-in-idUSKCN2270RX
Now to be accurate, I should say asymptomatic or very mild, because it’s possible you had the sniffles and are still shedding dead virus (for up to 12 weeks), but the point is 90-95% of people (depending on age) brush this off with no problems
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This is a second proof of pre-existing T-Cell immunity as a major factor in COVID-19 dynamics
It may be a combination of T-Cell with other immune response, but people’s immune system can fight off SARS-CoV-2
The first proof was in this thread (highly recommend this thread)
10 https://twitter.com/gummibear737/status/1298246346974154757
It may be a combination of T-Cell with other immune response, but people’s immune system can fight off SARS-CoV-2
The first proof was in this thread (highly recommend this thread)
10 https://twitter.com/gummibear737/status/1298246346974154757
Now let’s turn to antibody testing which, unlike PCR, can not amplify small amounts of RNA to a detectable quantity
If 90-95% of people have minimal levels of RNA, and are asymptomatic, then it’s logical that they are not producing much antibody
And hence not being detected
11 https://twitter.com/BallouxFrancois/status/1276855250083856386
If 90-95% of people have minimal levels of RNA, and are asymptomatic, then it’s logical that they are not producing much antibody
And hence not being detected
11 https://twitter.com/BallouxFrancois/status/1276855250083856386
Consider this big AB study in Italy which found only 2.5% AB positive
“Hint: ~37% testing positive lost taste/smell but only ~25% of people losing smell/taste tested positive”
That’s just not possible. Since we know so many are asymptomatic, its clear the %s are way off
12 https://twitter.com/BallouxFrancois/status/1290632180897665026
“Hint: ~37% testing positive lost taste/smell but only ~25% of people losing smell/taste tested positive”
That’s just not possible. Since we know so many are asymptomatic, its clear the %s are way off
12 https://twitter.com/BallouxFrancois/status/1290632180897665026
Remember the famous Bergamo 57% infected study?
This one result really messed with my thinking because it indicated that without mitigation, everybody can get infected
This had to be a variable I account for in any model of COVID-19
13 https://www.reuters.com/article/us-health-coronavirus-italy-antibodies/over-half-of-people-tested-in-italys-bergamo-have-covid-19-antibodies-idUSKBN23F2JV
This one result really messed with my thinking because it indicated that without mitigation, everybody can get infected
This had to be a variable I account for in any model of COVID-19
13 https://www.reuters.com/article/us-health-coronavirus-italy-antibodies/over-half-of-people-tested-in-italys-bergamo-have-covid-19-antibodies-idUSKBN23F2JV
Except, when a new countrywide AB study was released a couple months later, seroprevalence in Bergamo had dropped from 57% to 24%
A decrease of 2.4x
So the problem that we have is that because so many are asymptomatic, they produce low AB counts, and the ABs wane quickly
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A decrease of 2.4x
So the problem that we have is that because so many are asymptomatic, they produce low AB counts, and the ABs wane quickly
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Remember the big Spanish AB studies from June-July
They did two runs of tests about 6 weeks apart in late April and early June
Even though infections were still happening during that period, the seroprevalence remained virtually unchanged
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They did two runs of tests about 6 weeks apart in late April and early June
Even though infections were still happening during that period, the seroprevalence remained virtually unchanged
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We cannot accurately know what % of the population has been infected because it’s too late
We will never identify the asymptomatic infections from 3-4 months ago
When people talk about herd immunity at 10-20%, that’s only what they can measure
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We will never identify the asymptomatic infections from 3-4 months ago
When people talk about herd immunity at 10-20%, that’s only what they can measure
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Let’s assume 40% asymptomatics go IgG negative early and so you lose them right off the bat
The rest will slowly fade away over the next months
If 95% are asymptomatic, you will be undercounting infected by X fold depending on how long after infection you test
17 https://twitter.com/ballouxfrancois/status/1275022730660909056
The rest will slowly fade away over the next months
If 95% are asymptomatic, you will be undercounting infected by X fold depending on how long after infection you test
17 https://twitter.com/ballouxfrancois/status/1275022730660909056
So this why a measurable 10-20% can be herd immunity
You’re looking at a far bigger percentage in reality
It doesn’t take complicated SIR modeling to explain it (but feel free to do so if you want)
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You’re looking at a far bigger percentage in reality
It doesn’t take complicated SIR modeling to explain it (but feel free to do so if you want)
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Still not convinced?
AB studies consistently report asymptomatics as representing 25-35% of AB positive
But PCR which is far more sensitive and can amplify RNA from a trace amount, says 95% are asymptomatic
See the difference?
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AB studies consistently report asymptomatics as representing 25-35% of AB positive
But PCR which is far more sensitive and can amplify RNA from a trace amount, says 95% are asymptomatic
See the difference?
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What does all this mean?
1) The denominator of those who’ve been infected is much larger than we know
IFR is much lower than we have calculated - lower by a factor of 3-4x - probably about 0.1% -so a bad flu season
2) @MLevitt_NP2013’s Burnout is likely to be herd immunity
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1) The denominator of those who’ve been infected is much larger than we know
IFR is much lower than we have calculated - lower by a factor of 3-4x - probably about 0.1% -so a bad flu season
2) @MLevitt_NP2013’s Burnout is likely to be herd immunity
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3) Asia-Oceania immunity makes more sense in the context where they might only have 5% more asymptomatics but that means they have 99.75% asymps compared to 95% in Europe + Americas.
4) Many, many of you have already been infected and just don’t know it yet
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4) Many, many of you have already been infected and just don’t know it yet
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5) Continued lockdowns make no sense
6) Some % of asymptomatics spread, otherwise can’t explain how virus circulated
7) The disease COVID-19 only affects about 5% of population
8) With an IFR of 0.1% and assuming 220k total deaths, we’ll have 220 million infected in USA
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6) Some % of asymptomatics spread, otherwise can’t explain how virus circulated
7) The disease COVID-19 only affects about 5% of population
8) With an IFR of 0.1% and assuming 220k total deaths, we’ll have 220 million infected in USA
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In the end, COVID-19 will go the way of the 1957 pandemic
We will have the same deaths/million
The world didn’t stop then, sports weren’t cancelled, it was a fairly unremarkable event
Highly recommend you read this thread for some historical context
23 https://twitter.com/gummibear737/status/1287056551245733888
We will have the same deaths/million
The world didn’t stop then, sports weren’t cancelled, it was a fairly unremarkable event
Highly recommend you read this thread for some historical context
23 https://twitter.com/gummibear737/status/1287056551245733888
That’s it
Hope it wasn’t too long
If you enjoyed please RT the first tweet
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Hope it wasn’t too long
If you enjoyed please RT the first tweet
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