I'd be interested in if there was a gene that significantly reduced covid infection likelihood - but somehow didn't affect much else, like other viral infection

I'd be interested in if there was a gene that significantly reduced covid infection likelihood - but somehow didn't affect much else, like other viral infection rates. That would almost be a natural sort of experiment, to compare the IQ of these and other population. Though, you would have to have enough people in this group, not be too rare. And it would help if there was already a large population that was IQ measured prior to Covid, and could be re-measured. It seems unlikely that such a scenario exists.