Vitamin D supplementation as an important factor in COVID-19 prevention and treatment: what evidence do we have?

The immunomodulatory effect of vitamin D and its potential in prevention and treatment of acute respiratory infections have long been of interest to many scientific teams around the world. Several meta-analyses in the last 10 years have confirmed the protective (albeit of modest size) effect of vitamin D against respiratory infections. Because of many overlapping risk factors for vitamin D deficiency and severe COVID-19 infection, many experts believe that vitamin D supplementation could play an important role in prevention and treatment of the new coronavirus disease. Based on available data on the immunological action of vitamin D, it is possible that vitamin D could modulate the bodys response to SARS-CoV-2 infection both in the early viraemic phase and in later hyperinflammatory phase typical for the severe course of the disease. The first available data from epidemiological studies suggest that low serum vitamin D levels are associated with increased susceptibility to the new coronavirus infection as well as with severe course of the disease.