Covid causes brain damage. The common symptom of "loss of smell" was found to actually be due to covid infection of the neurons in brain & cranial nerves. Obviously "brain fog" (or memory issues, fatigue, lack of focus, however people articulated it) is due to damage to brain.
I wonder how society moves forward. We didn't get the movie-horror-story virus that turns people into zombies, but we did get a virus that leaves many people with diminished emotional regulation, attention span and ability to reason.