Here’s an article re: genetics:
https://www.sciencemag.org/news/2020...PFaL4dlUZ-lrU#
By the way, I misspoke. The blood type laddering is in regard to likelihood of infection, not severity post infection. (See link within article.). Though this could be misleading, as it might be that type O carriers aren’t registering as infected as much because many are infected but simply do not have any symptoms due to protective genetics correlated with O blood and therefore never get tested.
