If you ignore the extensive literature describing vitamin D's multi-pronged involvement in metabolism then your final sentence is entirely reasonable. Here's a

If you ignore the extensive literature describing vitamin D's multi-pronged involvement in metabolism then your final sentence is entirely reasonable. Here's a very short summary of some of the effects whereby vitamin D may may be causatively involved in the strongly demonstrated (there are numerous accounts in the literature) inverse relationship between vitamin D levels and the severity of COVID infection. Incidentally the focus should be not on how much vitamin D is taken as a supplement but on the actual blood level. Tons of references on what this should be rather my quoting those levels here. https://www.alliedacademies.org/articles/potential-mechanisms-for-vitamin-d-protective-effect-for-covid19-morbidity-and-mortality.pdf https://www.alliedacademies.org/articles/potential-mechanism...