Interesting project offering a $100,000 bet that vitamin D reduces Covid mortality. If you were skeptical of that trial, here's your chance to make some money on that belief.
This follows quite a lot of observational evidence. There are currently 11 studies that have found an association between serum vitamin D and Covid severity. These are listed here:
> "Both sides will agree in advance on the specifics of how a winner is determined, and what arbitration mechanism to use, if need be."