[matthew fuller]

"Vitamin D has long been know to help regulate immune responses to viral respiratory ailments in general. By now I think that it is generally accepted fact that D helps with SARS-CoV-2. "

At least one of the Vitamin D authorities that I have read is of the opinion that oral Vitamin D supplements are inferior to Sunlight/skin internally generated vitamin D. While I give that some credence, I have recently increased my oral D from 2000IU to 4000IU per day while still spending a lot of time on the trail (Central TX). The quoted opinion is from Dr. Michael F. Holick, Ph.D, M.D. in "The Vitamin D Solution" But was from memory, not verbatim.

[fso301]

At least one of the Vitamin D authorities that I have read is of the opinion that oral Vitamin D supplements are inferior to Sunlight/skin internally generated vitamin D.

Probably because vitamin D is just one part of the enormously complicated interaction between sunlight and our immune systems.