A French study found that long covid is barely associated with having had covid according to an antibody test, yet associated with believing one has had covid (which itself is unrelated to the antibody test results).
Sorry, are you claiming that “belief in covid” is uncorrelated with antibody test results? I think:
That’s a wild claim (people are seriously no better than random at determining if they’ve had covid?).
As far as I can tell, the study doesn’t claim that.
At a glance, the most important result of the study seems to be that antibodies are correlated with long covid as long as you don’t control for belief-in-covid; but antibodies are not associated with long covid once you do control for belief-in-covid. That makes a lot of sense if antibodies and belief-in-covid is very correlated with each other, but is harder to explain otherwise.
Relatedly, your story for why the french study doesn’t imply that covid is psychosomatic is way more extreme than it needs to be. Claiming that you have long covid is totally associated with having covid, as long as you don’t control for belief-in-covid. See e.g. this post.
Right, there is a ton of misunderstanding regression floating around on this issue it seems. Yet, one would still think that Having covid would be more predictive of Long covid than Believing you’ve had covid, since Believing and Long ought to be correlated only through their shared association with Having (common cause rather than mediation). The fact that this is not the case could indicate that people with chronic conditions come to think they Had covid (discussed at the end of the study) or that the measure of Having covid is not that good (see Siebe’s comment), or that it’s psychosomatic (loose usage of the term), or something(s) else.
Adding to the uncertainty is that “less than half of those with a positive serology test reported having experienced the disease.” This is especially troublesome since participants were informed of their serology results prior to the self-reports, so that’s some weird denial (or misunderstanding). However, that doesn’t mean they are unassociated! They are associated! (Table 2) Only 2% of seronegatives believed they had covid, but 42% of seropositives did. Having-->Believing, so that’s good at least.
Yet, one would still think that Having covid would be more predictive of Long covid than Believing you’ve had covid, since Believing and Long ought to be correlated only through their shared association with Having (common cause rather than mediation). The fact that this is not the case could indicate that people with chronic conditions come to think they Had covid (discussed at the end of the study) or that the measure of Having covid is not that good (see Siebe’s comment), or that it’s psychosomatic (loose usage of the term), or something(s) else.
Or that long covid is mainly caused by symptomatic covid, and Believing is a better predictor of symptomatic covid than antibody tests. Which seems pretty likely.
Sorry, are you claiming that “belief in covid” is uncorrelated with antibody test results? I think:
That’s a wild claim (people are seriously no better than random at determining if they’ve had covid?).
As far as I can tell, the study doesn’t claim that.
At a glance, the most important result of the study seems to be that antibodies are correlated with long covid as long as you don’t control for belief-in-covid; but antibodies are not associated with long covid once you do control for belief-in-covid. That makes a lot of sense if antibodies and belief-in-covid is very correlated with each other, but is harder to explain otherwise.
Relatedly, your story for why the french study doesn’t imply that covid is psychosomatic is way more extreme than it needs to be. Claiming that you have long covid is totally associated with having covid, as long as you don’t control for belief-in-covid. See e.g. this post.
Edit: See also the comment I wrote here.
Right, there is a ton of misunderstanding regression floating around on this issue it seems. Yet, one would still think that Having covid would be more predictive of Long covid than Believing you’ve had covid, since Believing and Long ought to be correlated only through their shared association with Having (common cause rather than mediation). The fact that this is not the case could indicate that people with chronic conditions come to think they Had covid (discussed at the end of the study) or that the measure of Having covid is not that good (see Siebe’s comment), or that it’s psychosomatic (loose usage of the term), or something(s) else.
Adding to the uncertainty is that “less than half of those with a positive serology test reported having experienced the disease.” This is especially troublesome since participants were informed of their serology results prior to the self-reports, so that’s some weird denial (or misunderstanding). However, that doesn’t mean they are unassociated! They are associated! (Table 2) Only 2% of seronegatives believed they had covid, but 42% of seropositives did. Having-->Believing, so that’s good at least.
Or that long covid is mainly caused by symptomatic covid, and Believing is a better predictor of symptomatic covid than antibody tests. Which seems pretty likely.
Yes!