[yazboo]

> 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.