Abstract
Novel corona virus disease (COVID-19) pandemic has seriously affected the entire world; moreover, infection and case fatality rate is quite high in countries located in North Hemisphere, where a large proportion of the population is living with Vitamin D (Vit D) deficiency. Vit D is a secosteroid hormone, which plays an important role in calcium and phosphorous homeostasis, and hence bone strength and also has a significant role in the immune health of an individual. It induces the expression of antimicrobial peptides that can decrease viral replication and also reduces the level of pro-inflammatory cytokines while enhancing the level of anti-inflammatory cytokines. Vit D supplementation in daily single doses (300–2000 IU/day) for 8–12 weeks had more protective effect for viral infections than large doses given at fixed intervals (100,000 or 200,000 IU per month or every 3 months). This evidence based review emphasizes the role of Vit D in the immune response to viral infections and proposes the immense value of Vit D supplementation, for the prevention and treatment of COVID-19.