I don’t know I would push Vitamin D as a “cure”. We know it helps bone density, that’s reason enough to monitor and correct it. I had one patient tell me after starting Vitamin D, “Now I can think clearly again!”. I wouldn’t rush out and start claiming I had found a cure for Alzheimer’s based on that. Unless maybe I was French.
Precisely, I would not suggest Vitamin D as a cure, either, my FRiend.
I do believe that there is evidence that Vitamin D can reduce the severity and duration of several enveloped virus infections (influenza for example). It's as inexpensive a getting 15-20 minutes of (non-sunscreened) sunshine per day, and the benefits might outweigh the risks. Any true benefit from Vitamin D for the china virus remains to be validated.
The field is wide open for some epi research (case severity vs blood vit D, etc.) And, much of this could be accomplished currently.
(I'm not a doc, this is not med advice, everyone should do their own DD, just open thoughts from a scientist who reads a lot.)