Although this is a notable finding it's important to remember that it doesn't lead to the conclusion that supplementing vitamin D will be very beneficial here. When vitamin D is produced in the body naturally via exposure to sunlight there's a huge amount of other things that occur as well, and we don't have a ton of good science to back up if curing a vitamin D deficiency via supplementation of pure vitamin D is rea…
I don't know what you mean by 'a ton', but there is good evidence that Vitamin D supplements do provide much of the same benefit [0] [1].
> Ultraviolet radiation (either from artificial sources or from sunlight) reduces the incidence of viral respiratory infections, as does cod liver oil (which contains vitamin D).
[0] https://pubmed.ncbi.nlm.nih.gov/16959053/
[1] https://sci-hub.se/https://www.sciencedirect.com/science/art...