In this long YouTube video, Dr. Seheult talks about many studies that show that low levels of vitamin D3 are associated with higher levels of CoVID19 infection and worse outcomes. The body’s level of vitamin D is associated with skin color, sunlight exposure and the latitude where people live. The moral is that you should take vitamin D3 supplement if your blood test shows less than 50 ng/ml. Mine was 42 so I take two 2000 IU pills a day.