Margarucci LM, Montanari E, Gianfranceschi G, et al. The role of vitamin D in prevention OF COVID-19 and its severity: an umbrella review: Vitamin D versus COVID-19: an Umbrella review. Acta Biomed. 2021;92(S6):e2021451. doi:10.23750/abm.v92iS6.12216