Does the long Covid first have psychological springs?
A study published Monday, November 8 suggests it but arouses the anger of patients as well as many scientific criticisms of its methodology, a controversy which highlights above all how much this disorder remains vague and ill-defined.
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Long Covid is characterized by the persistence of symptoms in a patient affected months earlier by Covid-19, including mild forms. However, these symptoms "
could most often be associated with believing to have been infected
" with the coronavirus, suggests a study published earlier this week in the Journal of the American Medical Association (Jama), one of the world's leading medical journals. . In other words, the long Covid would be above all psychological, unrelated to the reality of a virus infection, and therefore with physiological sequelae.
The study, coordinated by Cédric Lemogne, head of the psychiatry service at Hôtel-Dieu in Paris, looked at around 25,000 people followed for months by the French public health authorities to assess multiple effects of Covid.
On the one hand, these people have responded to questionnaires, both to say whether they have been ill and whether they are still feeling symptoms long afterward.
On the other hand, the reality of their disease was measured by serological tests which make it possible to confirm or not an infection a posteriori.
Critics of the methodology
The study concludes that most of the symptoms associated with long Covid are much more associated with claiming to be a former patient than having been tested positively, even if these two situations logically overlap a lot.
In patients who complain of long-lasting symptoms, it is therefore necessary to seek to "
identify cognitive and behavioral mechanisms
" and be careful not to "
attribute them by mistake to a Covid-19 infection
", conclude the authors.
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Immediately, the anger seized the associations of patients with long Covid who accuse the study of denying the reality of their disorder by giving it an essentially psychological explanation. This study gives rise to interpretations "
stigmatizing, dangerous and harmful for long Covid (s), especially as they are contested and not recognized by the entire scientific community and international associations
", ruled Thursday the French association AprèsJ20, also very virulent against an article in
Le Monde
relaying this publication.
And the criticisms are far from being the only fact of the patient associations, some of which are calling for the withdrawal from the study.
Many researchers have expressed their skepticism about the methodology adopted by this study.
"
A serological test (...) is not reliable as a marker of a previous infection
", judges the British virologist Jeremy Rossman, quoted by the organization Science Media Center.
This is the main objection against this study.
A serological test is more likely to "
miss
" a past Covid than to report it in error, which skews the results.
Risks of instrumentalisation
The authors of the study defended themselves, in the
World
, by stressing in particular that their study showed an association between a real infection and a lasting symptom: the loss of smell. According to them, this is proof that their method can distinguish which supposed manifestations of long Covid are actually linked to an infection. Because this disorder remains very vaguely defined and this controversy also highlights the difficulty of framing research on the subject. There are many symptoms associated with this disorder, one of which is fatigue or shortness of breath, which makes it difficult to determine to what extent long Covids cover different realities and, let alone, what may be the cause.
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In this context, the controversial
Jamaican
study risks being used "
to assert that (the long Covid) is absolutely not a problem
", fears the American doctor F. Perry Wilson, professor at Yale, on the Medscape site .
But, while also showing himself to be very critical of the study, he warns of a fundamental problem regarding the too vague definition of the long Covid.
“
We have to realize that with vague symptoms, we get vague diagnoses
,” he concludes.
"
In the absence of stricter criteria, many people risk receiving a
'
Covid long
'
label
when they are not affected at all
."
