On the study, even if the antibody test isn’t that accurate, one would still expect people with confirmed covid to have more long covid symptoms than people without confirmed covid. In fact, the study finds that belief in having had covid is a stronger predictor than confirmed covid, which suggests that the symptoms are caused by something else.
But people who have had COVID do have more Long Covid, if actually use an accurate measure (PCR testing). I report multiple studies in the post with control groups.
In the study, people with positive serology HAD more of 10 specific symptoms, even though serology is very inaccurate. Only when controlled for belief did that disappear. But belief in having had COVID has strong confounding effects:
if you have lasting effects, of course you’re more likely to identify a prior infection
if you had more clear acute symptoms, you’re more likely to have both belief you’ve had COVID, as well as that you’re more likely to develop Long Covid
they say that belief and serology were not correlated, but I’m confused by that. In the belief+ group, half had positive serology. In the belief- group, it’s like 2%?
If you control a weak predictor by a strong predictor correlated with the weak predictor, I’m not surprised that significant effects disappear.
The study also had data on PCR testing but didn’t use that in any way, which seems suspicious to me.
Also, in 2020 the base rate for other communicable diseases dropped a lot (flu dropped by factor 50x)
The problem with PCR test controls is that they would only catch an infection around the time you get infected, whereas antibody tests would catch infections further back in time.
I don’t see the evidence that belief in having had covid is a better predictor of having had covid than is a serology test.
On the study, even if the antibody test isn’t that accurate, one would still expect people with confirmed covid to have more long covid symptoms than people without confirmed covid. In fact, the study finds that belief in having had covid is a stronger predictor than confirmed covid, which suggests that the symptoms are caused by something else.
But people who have had COVID do have more Long Covid, if actually use an accurate measure (PCR testing). I report multiple studies in the post with control groups.
In the study, people with positive serology HAD more of 10 specific symptoms, even though serology is very inaccurate. Only when controlled for belief did that disappear. But belief in having had COVID has strong confounding effects:
if you have lasting effects, of course you’re more likely to identify a prior infection
if you had more clear acute symptoms, you’re more likely to have both belief you’ve had COVID, as well as that you’re more likely to develop Long Covid
they say that belief and serology were not correlated, but I’m confused by that. In the belief+ group, half had positive serology. In the belief- group, it’s like 2%?
If you control a weak predictor by a strong predictor correlated with the weak predictor, I’m not surprised that significant effects disappear.
The study also had data on PCR testing but didn’t use that in any way, which seems suspicious to me.
Also, in 2020 the base rate for other communicable diseases dropped a lot (flu dropped by factor 50x)
The problem with PCR test controls is that they would only catch an infection around the time you get infected, whereas antibody tests would catch infections further back in time.
I don’t see the evidence that belief in having had covid is a better predictor of having had covid than is a serology test.