I want to believe this, however, as far as I can tell, the design finds a correlation between severity of covid and IQ. One other possible explanation is that h

I want to believe this, however, as far as I can tell, the design finds a correlation between severity of covid and IQ. One other possible explanation is that healthy immune system correlates both with lesser covid symptoms and higher IQ (less inflammation/whatever). As another comment has mentioned, the best way to try to measure for this would be to have a pre-post, which could only be done on those who hadn't had it yet at the time of the first test but then later got at. Since vaccines are now a factor, and may correlate to intelligence, the study may not be possible in an ethical manner.