Association of Self-reported COVID-19 Infection and SARS-CoV-2 Serology Test Results With Persistent Physical Symptoms.., 2021, Matta et al

Michiel Tack said:
Don't think your blog needs to be changed a lot because all your arguments remain valid (they actually become even more so). A footnote will do I think or simply strikethrough 40 and write 60.

Thanks very much for keep on writing about flawed papers on ME/CFS and long covid.
Click to expand...
I have tweaked it to "at least 40%" -- when you publish your reply in JAMA Int Med, I will link to it in a footnote!
 
Instead of psychogenic, here's a potential (simplistic) biological explanation -

  1. There is something unusual with the large number of false negative serology results (in reference to patients' reported earlier symptoms)
  2. There is a large drop off in detectable immunoglobulins and an increase in break-through infections, post vaccination (prompting boosters)
  3. It's reported that the anti-SARS-CoV-2 antibody can be abnormally glycosylated and becomes a prothrombotic stimulus for platelets
  4. Long lived, potentially bioactive micro-clots have been demonstrated in Long Covid patients

What if these patients' antibodies are all sequestered in microclots that form around them?

They'd either get promptly cleared via circulating monocytes or (in Long Covid) persist, ineffectively.
Either way, they'd be undetectable in serology tests.
 
In the latest of his splendid blog posts Brian Hughes said:
But crucially, according to these researchers, participants whose SARS-CoV-2 infections were confirmed by laboratory tests appeared to exhibit much fewer symptoms than participants whose antibody tests came back negative.

The researchers’ implication was clear: the symptoms of long COVID that you hear about in media reports arise mostly in people who believe they had COVID, but who actually never had. Real COVID infections, by contrast, cause few lasting symptoms (and mainly just anosmia).

Nice story.
Click to expand...

@Brian Hughes I think they've got it exactly backwards.
 
People who don't make antibodies to SARS-2 might just have T cells that are prepared to deal with SARS-2 due to previous exposure to structurally similar viruses.

Pre-existing polymerase-specific T cells expand in abortive seronegative SARS-CoV-2
https://www.nature.com/articles/s41586-021-04186-8

I have repeatedly read that long covid patients are more likely to be in the no antibodies category.
 
Last edited:
Michiel Tack said:
26823 (total cohort) x 0.96 (number that did not get infected) * 0.025 (that was negative but got a positive result) = 644 false positives.
Click to expand...
So I understand. "(number that did not get infected)" ... was that identified by some mean other than the test method whose results are being debated here?
 
Michiel Tack said:
Don't quite get what you mean. Could you rephrase or elaborate?
Click to expand...
I don't think it is of great import anyway, was just being pernickety. But the figure of 96% who did not get infected, was determined using the serology test method, that itself has a 2.5% chance of incorrectly identifying people as not having been infected. Felt like the calculation could only be fully valid if the number of uninfected people in the equation was the true number; given it instead has to be the value indicated by the serology test itself, and thereby not independent, I was not sure if the calculation would be a bit different if needing to account for that.

But I think I might be tying myself up in knots here!
 
Do you mean: how was the specificity and sensitivity of the antibody testing determined in the first place? What did they use as gold standard to compare it to?

I personally don't know, I assume PCR testing?
 
Michiel Tack said:
Do you mean: how was the specificity and sensitivity of the antibody testing determined in the first place? What did they use as gold standard to compare it to?

I personally don't know, I assume PCR testing?
Click to expand...
No. I think I may just be getting myself confused.
 
Merged thread

Claim that French study showed long COVID doesn’t exist misinterprets the study and fails to account for its limitations

This article :

Link : https://healthfeedback.org/claimrev...prets-study-fails-to-account-for-limitations/
Title : Claim that French study showed long COVID doesn’t exist misinterprets the study and fails to account for its limitations

is discussing this paper from JAMA :

Link : https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2785832
Title : Association of Self-reported COVID-19 Infection and SARS-CoV-2 Serology Test Results With Persistent Physical Symptoms Among French Adults During the COVID-19 Pandemic

DETAILS[from the first link]
Factually inaccurate: The study by Matta et al. was inaccurately interpreted by social media users to mean that long COVID doesn’t exist. However, the study’s authors didn’t make such a conclusion. Instead, they suggested that a diagnosis of long COVID should be made cautiously, as persistent symptoms associated with long COVID could also be caused by other illnesses.
Overstates scientific confidence: The study’s design doesn’t allow conclusions to be made about whether long COVID exists. For example, it used a serology test to detect past or present SARS-CoV-2 infection. This test detects the presence of antibodies against the virus. However, serology tests aren’t as sensitive as PCR tests. There is some evidence that people with long COVID also tend to have lower levels of antibodies and that a certain proportion of infected people don’t generate measurable levels of antibodies against the virus. This means that previously infected people could have been wrongly classified as negative for SARS-CoV-2 infection in the study.

KEY TAKE AWAY

Persistent symptoms of illness despite recovery from an initial infection have been documented by scientists following various bacterial and viral infections, such as in the case of myalgic encephalitis (ME), more commonly known as chronic fatigue syndrome. Long COVID, which bears some similarities to ME, is a poorly understood condition in which COVID-19 survivors continue to experience symptoms of illness weeks to months after recovering from the initial infection. These symptoms include fatigue, difficulty breathing, and difficulty thinking clearly, and can significantly impact a person’s quality of life.

FULL CLAIM: “Because it looks like ‘thinking you had covid’ produces pretty much all the long term symptoms. Having actual covid does not.”; “Long COVID doesn’t exist”

...

There is more discussion to the claim than I've posted, and it can be read at the first link above.
 
Last edited by a moderator:
So far this is by far the LC study that has gotten the most interest with physicians, as best as I can see. The asymmetry of bullshit works just as well in medicine, it turns out. You can tell how many are thirsty for this. It's easy to see how some people latch onto this opportunity, it's so easy, no real work required and unlimited funding and attention. All you have to do is be a pompous "provocative" jackass and people who didn't know your name start respecting you and praising your work. Something something perverse incentives...

Apparently there is a thread in the medicine's sub-Reddit on this study, but I deliberately avoid any discussion of this topic between physicians because it's too vile and this one appears to be no exception. If anyone has the courage to see what the average physician is thinking. Although it would be illuminating for long haulers, to see what they are facing, but just as demoralizing.
 
rvallee said:
Apparently there is a thread in the medicine's sub-Reddit on this study, but I deliberately avoid any discussion of this topic between physicians because it's too vile and this one appears to be no exception. If anyone has the courage to see what the average physician is thinking. Although it would be illuminating for long haulers, to see what they are facing, but just as demoralizing.
Click to expand...

Well I went there and had a look. Generally as advertised I'm afraid. Good news is this is commentary mostly from a subset of junior doctors and allied staff who don't know better and think it's appropriate to opine on such a forum. Bad news is this is commentary generally from junior doctors and allied staff, who have presumably been taught these attitudes by their senior colleagues.

I won't quote any of those comments, but many reference self-diagnosed chronic Lyme, POTS, MCAS etc.

Something of a redemption from a perhaps less likely quarter. The most reasonable, aware and decent responses I saw reading through were from two psychiatrists. They were comments that would not have been out of place here.

I agree. We should be able to say "we don't know" rather than say "this doesn't fit with any condition I've learnt, so it must be psychiatric". We're a few decades past that kind of mentality
Click to expand...

This might be the same story as chronic Lyme and as fibromyalgia. Unexplained medical symptoms don't mean nothing is wrong, just that we don't know what is wrong.

It could be psychosomatic. It could be some autoimmune/rheumatologic problem. It could be both. It could be the interaction of those things with a moment when unexplained symptoms go from whiny to a recognized and supported syndrome. That's part of what chronic Lyme has provided—support, a community, putative treatments and at least the hope of pursuit of treatments.
Click to expand...
 
As much as this is important, it still sort of accepts the lie that this is about "belief", rather than simply asking people to evaluate what happened, with awareness that they don't have perfect information about it. If you ask someone whether it rained last week, it can be framed as a belief, but it would be silly to make up a mental illness about that, whether right or wrong. This paper is entirely about the authors' perception, not reality.

Having to make decisions based on imperfect information is a necessity, no one ever has that outside of fake scenarios. In many cases in this study it was correct, and it doesn't mean anything more or less than whether it's not. In some cases it could have been wrong about Covid but could have been a flu, and without a test at the right time to know better it's impossible to tell.

It's still doesn't make the claim wrong, just inaccurate. And actually, far more accurate than what health care usually does, since they often deflect to irrelevant psychology stuff, far less accurate than being right about having been sick but being wrong about which specific virus.

Because frankly this is exactly like having to disprove every conspiracy theory just because conspiracy theorists have enough power to waste everyone's time. I really doubt physicians would fare any difference if they had the same information available to them. Medicine really has to do better with this stuff, but instead here we are, talking nonsense where all the details are suspicious and everyone involved is biased anyway.
 
You must log in or register to reply here.
Back
Top Bottom