I do not understand why the "talking heads" are not promoting Vitamin D supplementation as a way of having mild Covid-19 disease rather than ICU disease! If you google "COVID VITAMIN D" there are a ton of excellent papers that associate severity of illness with serum levels higher than usual - 40-50ng/mL instead of 20-30. Taking 5,000 IU per day is cheap and strongly advised. Much easier than changing blood type or your genetics! Increasing serum Vitamin D has been associated with reduction in respiratory disease for > 50 years. This is no exception. There is even a paper that correlates severity of disease in different European countries based on population values for Vit D. Germans routinely take supplementation and their levels are higher than Italians and Spaniards who don't because they live in sunny places!