“Effect of calcifediol treatment and best available therapy versus best available therapy on intensive care unit admission and mortality among patients hospitalized for COVID-19: A pilot randomized clinical study” https://www.sciencedirect.com/science/article/pii/S0960076020302764?via=ihub&inf_contact_key=dc65c6a1e486d52b45b278a0bd971e28bb81b9ded3d8b3c1b80fc8cf5b3ba7c9#bib0100 https://de.wikipedia.org/wiki/Calcidiol
enjoy.
