Prevalence and predictors of long COVID among non-hospitalised adolescents and young adults: a prospective controlled cohort study, 2022, Wyller et al

Here is a summary with key points by the authors. My bold:

Key Points

Question What are the prevalence and associated risk factors of post–COVID-19 condition (PCC) in young people after mild acute infection?

Findings This cohort study included 382 SARS-CoV-2–positive individuals and a control group of 85 SARS-CoV-2–negative individuals aged 12 to 25 years who were assessed at the early convalescent stage and at 6-month follow-up. When applying the World Health Organization case definition of PCC, prevalence at 6 months was 49%, but was also comparably high (47%) in the control group. PCC was not associated with biological markers specific to viral infection, but with initial symptom severity and psychosocial factors.

Meaning These findings suggest that persistent symptoms in this age group are related to factors other than SARS-CoV-2 infection, and therefore question the usefulness of the WHO case definition of PCC.
 
They seem to have as their control group people who were tested, presumably because they had Covid symptoms, but the test was negative. So the control group were sick too, the only difference being that a single test was negative. Given that tests aren't 100% accurate, the results may simply be showing that testing positive at a single time point in infection isn't a good basis for studies like this.
 
Trish said:
They seem to have as their control group people who were tested, presumably because they had Covid symptoms, but the test was negative. So the control group were sick too, the only difference being that a single test was negative. Given that tests aren't 100% accurate, the results may simply be showing that testing positive at a single time point in infection isn't a good basis for studies like this.
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This has been pointed out to them. Together with studies on how antibodies are not a good indicator of previous covid infection.
 
Trish said:
Good. Have they replied?
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Here is one from twitter:


Siri Ann Mauseth: The methodology has weaknesses. To use PCR and antibody tets have several pitfalls. Such as infected being labeled as controls https://nature.com/articles/s41579-022-00846-2

Joel Selvakumar: There are clearly weaknesses - but I don't know if I agree with this one. PCR and antigen testing have been performed at two timepoints; and smell/taste symptoms (proxy for false negatives) are extremely low in the control group.
 
Author list (my bolding of familiar names)

Joel Selvakumar
Lise Beier Havdal
Martin Drevvatne
Elias Myrstad Brodwall
Lise Lund Berven
Tonje Stiansen-Sonerud
Gunnar Einvik
Truls Michael Leegaard
Trygve Tjade
Annika E. Michelsen
Tom Eirik Mollnes
Fridtjof Lund-Johansen
Trygve Holmøy
Henrik Zetterberg
Kaj Blennow
Carolina X. Sandler
Erin Cvejic
Andrew R. Lloyd
Vegard Bruun Bratholm Wyller

Selected quotes from the paper

"When sequelae arise after mild acute infection, a subset of cases might fit the label of postinfective fatigue syndrome (PIFS), in which persistent symptoms and disability accompany scarce findings on standard clinical examination.4-7 In the aftermath of a wide array of infectious diseases, such as mononucleosis, Q fever, and giardiasis, multiple prospective cohort studies report that 10% to 15% of patients experience moderate to severe disability meeting the diagnostic criteria for PIFS, in line with current studies of PCC."

"Studies of PIFS have benefitted from an international case definition25 that is centered around the symptom of fatigue, which should be persistent from onset of the acute infectious event, severely affect daily activities, and not be caused by any other condition; diagnosed individuals must experience at least 4 of 8 additional symptoms (such as headache and concentration or memory problems). In contrast, the broad case definition of PCC established by the World Health Organization (WHO) encompasses any symptom occurring in the aftermath of acute COVID-19, does not require symptom persistence since the infectious event, and does not stipulate significant disability.1"

Reference 25 is to Fukuda definition of CFS.

This paper is basically another attempt by COFFI members and friends to push their "postinfective fatigue syndrome" agenda.
 
Studies of PIFS have benefitted from an international case definition25 that is centered around the symptom of fatigue, which should be persistent from onset of the acute infectious event, severely affect daily activities, and not be caused by any other condition; diagnosed individuals must experience at least 4 of 8 additional symptoms (such as headache and concentration or memory problems).

In contrast, the broad case definition of PCC established by the World Health Organization (WHO) encompasses any symptom occurring in the aftermath of acute COVID-19, does not require symptom persistence since the infectious event, and does not stipulate significant disability.1
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They do seem to have a point here. If the WHO definition results in prevalence rates of nearly 50% at 6 months, it can't be sufficiently specific enough. I think none of us are seeing such high rates of disabling illness.
 
Even prejudiced agenda pushing researchers can occasionally happen upon a truth - the WHO classification was at best a stop gap Pandemic response and its continued usefulness has to be in doubt. There are however some weaknesses in the observations of this paper - note the differences between COVID + and COVID - in the questions re:Extraordinary Fatigue, Empty Batteries, Respiratory symptoms, Chills and Feeling hot/cold. However I don't think those issues give a basis for defending the WHO classification - but perhaps brings into question the strength of the alternate application of PIFS.


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Hutan said:
If the WHO definition results in prevalence rates of nearly 50% at 6 months, it can't be sufficiently specific enough.
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This has always been an issue with reporting on "long Covid." If you're measuring anyone with any symptom at 3 months or even six months, the numbers will be enormous. Early on, when everyone in ME-world predicted this, I assumed most had in mind a magnitude on the order of 5% or a bit more, on the order of the Dubbo studies and what has been generally known about the prevalence of post-viral illness. The LC minimizers are using the maximal estimates, which are certainly likely inflated, and using that to shoot down the presence of persistent pathophysiological post-viral illness. It's a clever strategy.
 
Andy said:
In contrast, the broad case definition of PCC established by the World Health Organization (WHO) encompasses any symptom occurring in the aftermath of acute COVID-19, does not require symptom persistence since the infectious event, and does not stipulate significant disability
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This definition is clearly ridiculous, and you therefore end up with papers like this one!
 
dave30th said:
but did they rely on serology here? At a quick glance, I didn't see anything about that.
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I haven't read the study, but when the first author says in the tweet "PCR and antigen testing have been performed at two timepoints" made me believe they had taken PCR and antigen tests, and also did the proxy testing by asking about smell/taste.
 
Kalliope said:
When applying the World Health Organization case definition of PCC, prevalence at 6 months was 49%, but was also comparably high (47%) in the control group
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Sounds like they didn't apply the definition correctly because this is ridiculous. Or chose an interpretation of it that is useful to minimize, which is equally ridiculous. We already knew that Wyller is a terrible researcher, didn't need this garbage study to confirm it.

Like clockwork, I've already seen it promoted by prominent minimizers. Medicine has a huge problem with garbage studies and excessive bad faith, at a level that no other profession has to deal with. We so badly need AI medicine, at this point it's an existential need, this whole profession has hit a wall and can't get past by it. I don't think our civilization can survive with such a terrible healthcare profession, it's broken beyond repair.
 
rvallee said:
Sounds like they didn't apply the definition correctly because this is ridiculous. Or chose an interpretation of it that is useful to minimize, which is equally ridiculous. We already knew that Wyller is a terrible researcher, didn't need this garbage study to confirm it.

Like clockwork, I've already seen it promoted by prominent minimizers. Medicine has a huge problem with garbage studies and excessive bad faith, at a level that no other profession has to deal with. We so badly need AI medicine, at this point it's an existential need, this whole profession has hit a wall and can't get past by it. I don't think our civilization can survive with such a terrible healthcare profession, it's broken beyond repair.
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Rest assured as we have been told several times that after a study is published its weaknesses and limitations will be clearly stated and if the methodology is bad it could never be misused in any way!

Fitting for April's fools, really. (Although this was not said about this particular study, but about the LP study)
 
Trish said:
They seem to have as their control group people who were tested, presumably because they had Covid symptoms, but the test was negative. So the control group were sick too, the only difference being that a single test was negative. Given that tests aren't 100% accurate, the results may simply be showing that testing positive at a single time point in infection isn't a good basis for studies like this.
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Or more likely, they have another virus.
 
rvallee said:
Sounds like they didn't apply the definition correctly because this is ridiculous. Or chose an interpretation of it that is useful to minimize, which is equally ridiculous. We already knew that Wyller is a terrible researcher, didn't need this garbage study to confirm it.

Like clockwork, I've already seen it promoted by prominent minimizers. Medicine has a huge problem with garbage studies and excessive bad faith, at a level that no other profession has to deal with. We so badly need AI medicine, at this point it's an existential need, this whole profession has hit a wall and can't get past by it. I don't think our civilization can survive with such a terrible healthcare profession, it's broken beyond repair.
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Dare I ask what prominent minimizers?
 
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