https://articles.mercola.com/sites/articles/archive/2020/12/11/do-vitamin-d-supplements-help-prevent-respiratory-tract-infections.aspx?ui=42210682a9f532e62d4205500850cf31fb58fe001fe94cff753bd573acef4daf&cid_source=dnl&cid_medium=email&cid_content=art1ReadMore&cid=20201211&mid=DM744365&rid=1032316737

Vitamin D is lacking in those who die of Covid or have severe outcomes.