The
coronavirus disease 2019 (COVID-19) pandemic has led to a declaration of a Public Health Emergency of International Concern by the World Health Organization. As of May 18, 2020, there have been more than 4.7 million cases and over 316,000 deaths worldwide.
COVID-19 is caused by a highly infectious novel coronavirus known as
severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), leading to an acute
infectious disease with mild-to-severe clinical symptoms such as flu-like symptoms,
fever,
headache, dry
cough,
muscle pain,
loss of smell and taste, increased
shortness of breath, bilateral
viral pneumonia,
conjunctivitis, acute
respiratory distress syndromes,
respiratory failure,
cytokine release syndrome (CRS),
sepsis, etc. While physicians and scientists have yet to discover a treatment, it is imperative that we urgently address 2 questions: how to prevent
infection in immunologically naive individuals and how to treat severe symptoms such as CRS, acute
respiratory failure, and the loss of somatosensation. Previous studies from the 1918
influenza pandemic have suggested
vitamin D's non-classical role in reducing lethal
pneumonia and case fatality rates. Recent clinical trials also reported that
vitamin D supplementation can reduce incidence of acute respiratory
infection and the severity of
respiratory tract diseases in adults and children. According to our literature search, there are no similar findings of clinical trials that have been published as of July 1st, 2020, in relation to the supplementation of
vitamin D in the potential prevention and treatment for
COVID-19. In this review, we summarize the potential role of
vitamin D extra-renal metabolism in the prevention and treatment of the
SARS-CoV-2 infection, helping to bring us slightly closer to fulfilling that goal. We will focus on 3 major topics here: 1.
Vitamin D might aid in preventing
SARS-CoV-2 infection:
Vitamin D: Overview of Renal and Extra-renal metabolism and regulation.
Vitamin D: Overview of molecular mechanism and multifaceted functions beyond skeletal homeostasis.
Vitamin D: Overview of local
immunomodulation in human
infectious diseases. Anti-
viral infection. Anti-
malaria and anti-
systemic lupus erythematosus (SLE). 2.
Vitamin D might act as a strong
immunosuppressant inhibiting
cytokine release syndrome in
COVID-19:
Vitamin D: Suppression of key pro-inflammatory pathways including
nuclear factor kappa B (
NF-kB),
interleukin-6 (IL-6), and
tumor necrosis factor (TNF). 3.
Vitamin D might prevent loss of neural sensation in
COVID-19 by stimulating expression of
neurotrophins like
Nerve Growth Factor (
NGF):
Vitamin D: Induction of key
neurotrophic factors.