Maybe different strains or something? To me, it seems like the severity of the reaction must have some kind of DNA link. Where certain people with certain genetic traits are more susceptible to the harsh symptoms of Covid and/or the vaccine. I would assume they are trying to figure that out, too. Did you do any treatments for your original run with covid? And, just as I wrote that, I wonder if someone had symptoms from the vaccine, if Ivermectin or other treatments would lessen those, too.