> do you mean not every tests positive for seroconversion months after infection
This wasn't your point but I'm trying to see whether this is accounted for in the study. I don't think it is, unless I missed something.
The study's self-reported long COVID group is people who in the past 4 weeks experienced any symptoms that had been ongoing for 8+ weeks. If these infections were 8+ weeks ago, these people would probably be seronegative anyway. To put it another way, seronegativity now doesn't rule out an infection 2+ months ago, so for some of these people their belief that they had COVID may match reality more than this article implies.
I don't know if there is a way to reliably identify a 2+ month old infection but I think you would need that to be able to say anything definitive about the linkage.
This wasn't your point but I'm trying to see whether this is accounted for in the study. I don't think it is, unless I missed something.
The study's self-reported long COVID group is people who in the past 4 weeks experienced any symptoms that had been ongoing for 8+ weeks. If these infections were 8+ weeks ago, these people would probably be seronegative anyway. To put it another way, seronegativity now doesn't rule out an infection 2+ months ago, so for some of these people their belief that they had COVID may match reality more than this article implies.
I don't know if there is a way to reliably identify a 2+ month old infection but I think you would need that to be able to say anything definitive about the linkage.