Well, I don't know what to think about that. As an A+ person I guess I should be afraid and thankful that I sidestepped that landmine. (psst...I don't take the Flu shots and I have never had the flu. I might be screwing up all that scientific study.)
I’d be more inclined to believe that people with well-functioning immune systems, regardless of blood type, are less likely to get sick in general, and that would include Covid. I’m neither A nor O, but I’m not going to sweat finding out my supposed vulnerability based on blood. I did buy one of those books on eating optimally for your blood type, but disregarded it after I found out that so many otherwise healthy foods that I happened to love were supposedly “bad” for my blood type... go figure!