In recent months, since the Sars-Cov-2 pandemic has hit the entire world landscape, one of the most heated debates involving researchers has concerned the potential role that vitamin D could play in relation to infection by COVID-19.

In particular, numerous scientific studies have shown that the deficiency of this vitamin is present in a large part of the sick subjects, in a Spanish study¹ this association was reported in about 80% of the sample considered, furthermore other studies^2,3,4 attribute to this hormone a potentially protective role by stimulating type I interferon and enhancing innate immunity.

This review of the literature investigating, through a bibliographic search in the Pubmed - Medline database, aims to evaluate the possible association between vitamin D and Sars-Cov-2 infection in terms of outcomes such as: association between levels of vitamin D and infection, disease severity, mortality, analyzing a total of 274 studies, of which 8 reviews were finally evaluated, which allowed, through a review of the literature, to demonstrate a positive association of vitamin D in the prevention and treatment of infection from Sars-Cov-2 and in other pathologies such as flu, pneumonia and chronic diseases such as diabetes, obesity and arterial hypertension, or conditions favorable to complications during Covid-19 infection.