When this mess blew up in early 2020 I went on the reddit COVID19 board and they had a lot of studies posted about the current knowledge of the pandemic and viral infections in general.

There was a very strong signal even then that "adequate" vitamin D levels was associated with better out comes from the rona. At that point, in March, we started eating vitamin D like Pezz candies. We test near 100 which some say is nearly toxic, but if you dose it with Vitamin K your toxicity which is usually expressed by hypercalcemia will be muted tremendously. D should be supplemented with K2 and magnesium to keep things in balance.

The upside for us is allergies are lessened and we have not had any cold symptoms at all. Also, we've been contact traced several times but came up with goose eggs.

One other point. Low vitamin D levels is heavily correlated with age, obesity, diabetes and oddly enough High Fructose Corn syrup consumption. The liver processes HFCS as well as the precursors for VD3. But the liver will favorably process the HFCS and leave the D3 in the queue- hence lowering the blood levels of D3. Stay away from HFCS as well as vegetable and seed oils as they suck as well!