Vitamin D and COVID-19: An Overview of Recent Evidence

Abstract

The novel coronavirus severe acute respiratory syndrome (SARS-CoV-2) has progressed rapidly from an outbreak to a global pandemic, with new variants rapidly emerging. Coronavirus disease 2019 (COVID-19), the disease resulting from SARS-CoV-2 infection, can lead to multiorgan damage. Due to the extremely contagious and fatal nature of the virus, it has been a priority of medical research to find effective means of treatment. Amid this search, the role of vitamin D in modulating various aspects of the innate and adaptive immune system has been discussed. This review aims to consolidate the research surrounding the role of vitamin D in the treatment and prevention of COVID-19. While there are some conflicting results reported, the consensus is that vitamin D has a host of immunomodulatory effects which may be beneficial in the context of COVID-19 and that low levels of vitamin D can result in dysfunction of crucial antimicrobial effects, potentially contributing to poor prognosis. Studies also show that the effects of low vitamin D can be mitigated via supplementation, although the benefits of vitamin D supplementation in the treatment of COVID-19 remain controversial.

Keywords: COVID-19; SARS-CoV-2; coronavirus; immunity; infection; review; vitamin D.

Figure 1

Potential mechanisms by which sufficient serum vitamin D levels may confer protective effects against coronavirus disease 2019 (COVID-19) and acute lung injury, whereas vitamin D deficiency may contribute to a defective immune response against COVID-19 and increased severity and/or mortality. ACE, angiotensin-converting enzyme; ANG, angiotensin; COVID-19, coronavirus disease 2019; RAAS, renin angiotensin aldosterone system; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2. Arrows pointing up indicate an increase; arrows pointing down indicate a decrease.