There was a doctor in a video I saw, I need to find it, but he explained that since vitamin D is fat soluble it’s easier to be deficient in it if you’re overweight or obese. It’s also easier to be more deficient in it the darker your skin is, since white skin is more sensitive to sunlight, which is why white people get skin cancer so much easier. Even a lot of white people need vitamin d supplements or more sunlight, especially the further north they are. Basically most patients in serious condition tested either vitamin d insufficient or deficient, when people have enough vitamin D, he said they just don’t die from Covid, and they don’t suffer from the flu as much either.