COVID-19 caused by SARS-CoV-2 virus has affected the lives of millions of individuals globally and also severely strained the medical community. Pre-symptomatic and asymptomatic SARS-CoV-2 positive individuals far outnumber the symptomatic ones or those with severe disease. The transmission potential of SARS CoV-2 is potentially greater than earlier viral outbreaks of SARS-CoV and MERS-CoV.Routine measures of social distancing, personal hand hygiene and limited outdoor contact activities have shown benefits to limit corona virus infection. However, the role of vitamin D in SARS-CoV-2 infection is sparingly explored despite the knowledge of an immunomodulatory role and protective effect of vitamin D against viral infections. Meta-analysis of five clinical trials of vitamin D supplementation found that those receiving vitamin D supplementation had fewer respiratory tract infections (odds ratio = 0.58 (95%CI, 0.42 - 0.81).Any immune-modulatory effect of vitamin D is likely to be observed at levels which are considered higher than that required for normal bone metabolism.

Inclusion Criteria:

1. RT-PCR proven SARS-CoV-2 infection or computed tomography scan findings compatible with the COVID19 disease (bilateral multifocal ground-glass opacities ≥50%)
2. Moderate to severe COVID-19 defined by PFR ratio of <200
3. SOFA score>4
4. Patients with vitamin D deficiency defined as 25 (OH)D level<20 ng/ml
5. Age>18 years

Exclusion Criteria:

• 1. Vitamin D sufficient or already receiving vitamin D supplements 2. Active malignancy 3. Hypercalcemia, hyperparathyroidism 4. Chronic kidney disease (eGFR<30 ml/min) 5. Pregnant and lactating women 6. Patient on mechanical ventilation at ICU admission