[giovonni]

There is (constant) ongoing research~ into how our Sun affects the human immune system and the effects (the amounts) of Vitamin D has upon us?

But~ I tend to go with the view that safe (skin protective) exsposure to sunlight and a nutritional balance diet (that includes an adequate supplement) with vitamin D {is Key} too fighting viral infection to the human body.

In the world of biology, it should be noted > all research data is collected & recorded in the terms of percentages~ of risk, incidence, statistical data,
there is...
No total immunity~ No 100% protection