According to experts such as Dr. William F. Marshall and the Mayo Clinic “There isn't enough data to recommend use of vitamin D to prevent infection with the virus that causes COVID-19 or to treat COVID-19, according to the National Institutes of Health and the World Health Organization.” However, he cites “several recent studies looked at the impact of vitamin D on COVID-19 and shown interesting results favoring the management of Vitamin D deficiency. One study of 489 people found that those who had a vitamin D deficiency were more likely to test positive for the virus that causes COVID-19 than people who had normal levels of vitamin D. Other research has observed high rates of vitamin D deficiency in people with COVID-19 who experienced acute respiratory failure. These people had a significantly higher risk of dying. And a small, randomized study found that of 50 people hospitalized with COVID-19 who were given a high dose of a type of vitamin D (calcifediol), only one needed treatment in the intensive care unit. In contrast, among the 26 people with COVID-19 who weren't given calcifediol, 13 needed to be treated in the intensive care unit. In addition, vitamin D deficiency is common in the United States, particularly among Hispanic and Black people. These groups have been disproportionately affected by COVID-19. Vitamin D deficiency is also more common in people who are older, people who have a body mass index of 30 or higher (obesity), and people who have high blood pressure (hypertension). These factors also increase the risk of severe COVID-19 symptoms.”