[Question] Efficacy of Vitamin D in helping with COVID

so a new research found that high dose of Vitamin D significantly improve out comes for COVID patient:

https://​​www.sciencedirect.com/​​science/​​article/​​pii/​​S0960076020302764?via%3Dihub

another source on facebook claim that:

- A study in Indonesia found that out of the patients that died from COVID-19, 98.9% of them were deficient in vitamin D, while only 4% of the patients with sufficient vitamin D died.

-A study of patients in New Orleans found that 84.6% of the COVID-19 patients in the ICU were deficient in Vitamin D while only 4% of the patients in the ICU had sufficient levels of Vitamin D.

-A study in the Philippines found that for every standard deviation increase in vitamin D people were 7.94 times more likely to have a mild rather than severe COVID-19 outcome and 19.61 times more likely to have a mild rather than critical outcome.

I couldn’t find any mention of this on lesswrong, [granted I haven’t look very hard], anyone who have done their reseach on this can help me determine the import of Vitamin D in fighting this pandemic?

and if it’s true, anyway we can profit from this? any stock or index fund?