Opinion Challenging the current hypothesis that thrombosis is responsible for the post-COVID-19 condition

Abstract:

People with the post-COVID-19 condition suffer symptoms that persist beyond 12 weeks following acute COVID-19 infection. Fatigue, shortness of breath, and cognitive dysfunction (“brain fog”) are common. Scientists, clinicians, and patients debate the pathophysiology. One pathophysiological hypothesis is that prothrombotic changes associated with acute COVID-19 persist, causing clots that lead to symptoms. This theory, arising from a research team in South Africa and supported by a paper in Nature Medicine, has been widely disseminated on social media and entered the public narrative as a cause of the post-COVID-19 condition.

We describe the development of this theory, examine the findings of a Cochrane review that critically appraises the “microclot” beliefs, and critically appraise the influential study relating clotting biomarkers to cognitive deficits. We conclude the inferences for the hypothesis are not based on evidence, unlicensed use of antithrombotic medication is not justified, and apheresis should not be considered outside of a well-designed clinical trial.

https://www.sciencedirect.com/science/article/pii/S2475037924001316

Study authors include Paul Garner and Alan Carson

 

So Garner and Carson are essentially using the microclots literature as a way to rubbish the biomedical literature around Long Covid writ large. Very telling that they write "Furthermore, there is a body of research in neuroscience, psychology, and evolution that explains the presence of PCC in those not severely unwell initially," citing the Oslo Fatigue Consortium's position paper. The standards of evidence they require from biomedical research are orders of magnitude greater than those they require of research supporting their own pet theory.

Also I'm in no position to evaluate the microclots literature, but their critiques of it seem a little weak and forced.

"The team found that the phenomenon termed “microclots” were not clots but amyloid fibrin(ogen) particles" - has this ever not been utterly obvious? There's a reason they applied a new term to the particles rather than calling them clots.

"These were also found in the studies appraised in healthy individuals, in patients with acute COVID-19, and in persons with diabetes" - this has also been known for a long time. The question isn't whether they're found in healthy people and people with other disease states, but whether there's a correlation between microclots and Long Covid.

"There was no evidence linking the amyloid fibrin(ogen) particles to the pathophysiology of PCC" - it's still early days in research into Long Covid and microclots. As far as I can tell, researchers are still at the stage of working out how best to identify and quantify microclots in an objective manner.

It just reads as an oversimplified hit job.

 

Is this the start of a new “false illness beliefs”, “false microclot beliefs”?

 

I looked up Paul Garner’s wikipedia page and it’s spewing the whole “wessley death threats” scenario happened to Garner… But the only citation is a substack blog. Dodgy.

 

Maybe David Jameson has been active again (who btw seems to also actively be reading on this site, so hi to you David )?

 

Hi David

 

I just realized that I've been blocked on X by Alan Carson? Wow. I only wrote one tweet to him months ago about 'keeping an open mind'.

 

Imagine listening to patients. I think you’re asking too much of professor Carson and Garner. /s

 

I think Garner and Carson are on solid ground in their critique of 'micro-clots' which aren't even micro-clots, they are precipitates in test tubes. I think the researchers are still at the stage of trying to find out whether they have measured anything real to be honest.

The story around micro clots is that they obstruct small blood vessels in living patients. But we know what obstruction of small blood vessels in living people looks like and we don't see that in Long Covid, so it seems a pretty dead horse to flog.

Their support of the Oslo Fatigue Consortium is obviously absurd, but that is a different issue.

 

I was hoping you’d chime in - I have 0 scientific background so have never known what to make of microclots. Always good to see what an expert makes of the evidence

 

Odd way to spend their time. There are pretty much no real arguments here, so I don't really know why this commentary exists other than to add a citation to their Cochrane review and their Oslo op-ed. Given the authors, however, this actually makes the hypothesis more interesting. They just have a special talent of being wrong, to the point where if they think something is wrong, it's more likely to be right.

But really there are no arguments here. This has been researched by a handful of people, and I'm pretty sure that there has been more attention devoted to dismissing it than at researching it. I almost never see this mentioned in the patient community other than as a research hypothesis, one of many. There are people willing to try anything, and that shouldn't be surprising given the level of disability, but the hypothesis isn't based on treatments, so it's mostly irrelevant here.

To actually cite themselves as evidence of a preferred alternative psychosocial explanation is pretty laughable, in part because of how completely hollow their entire argumentation is, far weaker than even the microclot theory, but also the fact that it's framed entirely as "fatigue syndromes", which is the majority of LC patients but far from all. And simply ignores PEM/PESE, which is even more common and the most disabling aspect, something they're still in denial of.

But at least this keeps them busy, away from their usual nonsense. So I guess that's good. The difference between the patient community and them of course is that we want to know what's really true and will accept the outcome of rigorous scientific research, in part because there are many hypotheses, while they have only one model, the same Freud came up with 150+ years ago. But that hasn't happened yet, because it is researched by a handful of people, less than the number of therapists an average rehabilitation clinic providing useless alternative medicine that is harmful to many.

I don't think they understand that in science, hypotheses aren't challenged in a debate, they are falsified by the scientific method. So frankly I welcome them doing that. In fact stand on every street corner with a trumpet and scream it loud. Nobody cares.

In fact, I think this deserves a meme:

 

Microclots don't explain PEM. 'Nuff said.

 

I wouldn't be so sure. The big problem with ME/CFS is that even the most mainstream biomedical inclined physicians specialising in it have a tendency to pick up fringe ideas like this. So, currently, people are being treated with triple anticoagulant therapy on the basis of 'micro clots' and by physicians who people with ME/CFS may have to rely on as their best medical allies. It is an uncomfortable situation.