The rational calculation here is very clear. Taking 1000 IU of Vitamin D a day has pretty much zero risk. Going outside in the sun around noon, without too mu

The rational calculation here is very clear. Taking 1000 IU of Vitamin D a day has pretty much zero risk. Going outside in the sun around noon, without too much clothing (or sunblock, of course!), for about 15 minutes a day also has pretty much zero risk. (In fact, it likely has benefits other than vitamin D, such as nitric oxide production, which lowers blood pressure.) There is substantial evidence that these measures would reduce severity of infections such as influenza and covid-19, at very small to zero monetary cost. It's not a certainty, of course, but it is highly unlikely that Vitamin D deficiency is actually protective against covid-19. Therefore, all public health organizations should be strongly recommending that everyone take 1000 IU of Vitamin D and get some sunlight, and heavily publicizing this recommendation. The fact that they are not doing this is sadly an indication that the people in charge of these organizations do not actually have a mental orientation of solving the problem. (As you probably know, there are many other indications of this as well.)