Takeaway: If you're vitamin D deficient, taking a D supplement reduces the incidence of acute respiratory infections by 70%.<p>Here is the study:
https://www.bmj.com/content/356/bmj.i6583<p>The study is a tough read, so here is a video explaining the results:
https://www.youtube.com/watch?v=W5yVGmfivAk<p>Since coronavirus is a respiratory illness, this could be a tool in slowing it's spread. Especially since most people get their D from UV light, which is in short supply in northern regions right now.
Needles to say, this applies only to vitamin D deficiency. Taking extra large amounts when you don't have deficiency is completely different issue.
Article about vitamin D deficiency in winter:<p><a href="https://www.nytimes.com/2018/02/16/well/live/do-i-get-enough-vitamin-d-in-the-winter.html" rel="nofollow">https://www.nytimes.com/2018/02/16/well/live/do-i-get-enough...</a>