I should ask my Dr if I'm at higher risk for complications but I keep not doing that? I don't know why? But if covid can create brain injury, the brain uses oxygen, and brain injuries affect the immune system, that does sound definitely plausible. But if there's a lack of study, it wouldn't surprise me because "haha brain damage" is a thing, so a lack of shits given by society at large is obvious. I think part of the reason I don't ask is because I would anticipate a casual shrug ghhdfbk.
Edit: I've done my Google and if you feel like it and find something more vague than "maybe, no special reason, maybe if your immune system is fucked up or something, anyway, wash your hands" I'm all ears.