Covid 19: adjuvant approaches etc,

[WillBrink]

What causes these Vitamin D deficiencies? Just lack of sun? Skin tone?

All the above. We humans were outside and working under the sun all day up until quite recently in our history. One hypothesis as to why white people exist is as they went into colder climates with less sun, skin got lighter to allow more D production. For all intel on that, D, etc best article on the net:

https://brinkzone.com/vitamin-d-what...to-achieve-it/