Various studies have found an association between severe vitamin D deficiency and COVID-19-related outcomes. Vitamin D plays a crucial role in immune function and inflammation. Recent data have suggested a protective role of vitamin D in COVID-19-related health outcomes. 4. Conclusions The current evidence supports the benefits of vitamin D interventions in patients hospitalized with COVID-19 due to the protective effect provided by vitamin D against ICU admission and mortality. A meta-analysis per se does not allow us to state whether the results are truly positive or false-positive. In addition, the inclusion of studies with large effect sizes and significant...