> My best guess is that in the United States especially, it's a combination economic/socitial factors and vitamin D deficiency that's making the virus have higher mortality in populations of racial minorities with darker skin

African American communities are hardest hit because of genetic and especially cultural practices which predispose them toward obesity, high blood pressure, heart disease, etc. Further, let's not pretend that African American communities have the same level of respect for authority (i.e. following recommendations/orders) as other groups (though to some degree that disdain may be justified, but that's another discussion).