Vitamin d deficiency is correlated to lower physical activity. We know health is correlated to Covid-19 outcomes. You need a double blind study to say there

Vitamin d deficiency is correlated to lower physical activity. We know health is correlated to Covid-19 outcomes. You need a double blind study to say there is evidence that it has a protective effect. https://pubmed.ncbi.nlm.nih.gov/28289868/ https://pubmed.ncbi.nlm.nih.gov/28289868/