The records of 1,176 patients admitted between April 2020 and February 2021 to the Galilee Medical Center (GMC) with positive PCR tests were searched for vitamin D levels measured two weeks to two years prior to infection. Patients with vitamin D deficiency (less than 20 ng/mL) were 14 times more likely to have severe or critical case of COVID than those with more than 40 ng/mL. Strikingly, mortality among patients with sufficient vitamin D levels was 2.3%, in contrast to 25.6% in the vitamin D deficient group.Bar-Ilan University. “Pre-infection deficiency of vitamin D is associated with increased disease severity and mortality among hospitalized COVID-19 patients: Study affirms that sufficient vitamin D levels may positively influence the outcome of infection.” ScienceDaily. http://www.sciencedaily.com/releases/2022/02/220203161135.htm (accessed February 6, 2022).
Links to a few older posts on the same topic.