Correlation between Serum Level of Vitamin D and Covid-19 Infection Severity: A Literature Review

In recent years, infectious diseases caused by viruses have become one of the biggest global health problems, including coronavirus disease 2019 (Covid-19) infection. Covid-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which can induce immune responses and inflammatory reactions, thereby leading to the damage of tissues. Hyperinflammation due to cytokine storm in infected patients increases the risk of severe infection and death. Vitamin D can also reduce the severity of infections because it acts as an immunomodulator. Therefore, this study aimed to determine the immunomodulatory effect of vitamin D on Covid-19 infections. A total of nine articles were collected using literature searching on several databases, such as PUBMED and Science Direct with the keywords of “Covid-19”, “immunomodulator”, and “vitamin D”. Five of them were observational or retrospective studies, which determined the correlation between serum concentration of vitamin D and Covid-19 infection severity. Meanwhile, another four articles were random clinical trials testing the effect of the drugs’s supplementation on infected people. The results showed that high levels of serum vitamin D can cause low concentrations of pro-inflammatory cytokines, which reduces the incidence of acute respiratory infections and the severity of the viral infection. Furthermore, vitamin D, specifically D3, has the potential to act as an immunomodulator in Covid-19 by reducing pro-inflammatory cytokines, thereby reducing the risk of severity.