Related
High-dose Vitamin D reduces disease activity in early multiple sclerosis onset (91 points, 15 days ago, 52 comments) https://news.ycombinator.com/item?id=43469661
Over 80% of Covid-19 patients in a hospital study have Vitamin D deficiency (654 points, 4 years ago, 363 comments) https://news.ycombinator.com/item?id=24912172
Adequate Vitamin D Levels Cuts Risk of Dying from Covid-19 in Half, Study Finds (372 points, 5 years ago, 211 comments) https://news.ycombinator.com/item?id=24607645
Those last two are not actually related.
This review was about testing supplementation of vitamin D, what you posted is mostly about correlation between serum levels and health outcomes, and those levels are largely about non-supplemented “natural” vitamin d.
The distinction is important because science has been trying to figure out whether vitamin d itself has the benefits, or if it is a marker for a larger salubrious process.