Abstract: In the world, the third big coronavirus (CoV) outbreak originated in late 2019 and is called COVID-19 in Wuhan, Hubei, China 1 . The epidemic first spread to nearby Asian countries and then across the world after an initial explosive outbreak of pneumonia of uncertain aetiology in China. The bilateral lung glassy opacity of patients with COVID-19 was found to have a constellation of symptoms such as flu, dry cough, dyspnea, sore throat, and nasal inflammation and radiological findings. vitamin D is subject to a range of ways, including physical barriers, cellular natural immunity and adaptive immunity, to lower risk of microbial infection and death. The supplementation with vitamin D has shown beneficial effects in viral influenza, including HIV infections. During Covid 19, the effects of vitamin D supplementation remain controversial. In order to help identify cut offs for vitamin D and, last but not least, which dose is the strongest, clinical trials are needed.