Description at VitaminDWiki.com

The study:

[Note: 10,000 iu vitamin D is not a high dose, but still shows significant results when given AFTER hospitalization]

Changes in the immune response against SARS-CoV-2 in individuals with severe COVID-19 treated with high dose of vitamin D

MontserratTorres…

Beneficial effect of supplementation with 10,000 IU/day was also observed in participants who developed ARDS and stayed at the hospital for 8.0 days, whereas those who received 2,000 IU/day stayed for 29.2 days (p=0.0381).