The role of vitamin D in COVID-19

This chapter investigates the role of vitamin D in SARS-CoV-2 infection and the development and severity of COVID-19 infection. This includes an introduction of COVID-19 infection and the pathophysiology of the disease. The immunological and antiinflammatory effects of vitamin D are presented relevant to COVID-19 infection. Key observation studies that have investigated an association between vitamin D and COVID-19 are reviewed, including both community and hospital based. Important research studies that have investigated the effect of vitamin D supplementation on COVID-19 are reviewed including published randomized controlled trials and systematic reviews. On review, there is currently insufficient evidence to recommend vitamin D supplementation solely for prevention or treatment of COVID-19. Further trials seek to investigate effect of vitamin D supplementation on COVID-19.