Thanks for the links!

Interestingly, these papers together are much stronger evidence than either apart. This is because they use different methods. The OP is a population level study, while the second link you shared is a retrospective individual level study.

While I have some concerns with the stats in both papers (I'm always suspicious of p-values close to the magic number of 0.05), this does seem like interesting research, and potentially very helpful to dealing with Covid-19.

The irony of course, is that I suspect many of the Northern latitude people with high levels of Vit-D may be getting it through tourism to Southern Europe, which is very unlikely to happen this year.