With low levels of vitamin D in critically ill patients with COVID-19 reported in numerous recent studies, and evidence supporting the reasonably good absorption of enterally administered vitamin D, researchers conducted a study to determine the outcomes of boosting low levels in the vitamin D to Improve Outcomes by Leveraging Early Treatment (VIOLET) trial. For the study, 2,624 critically ill, vitamin D-deficient patients at high risk for death were administered a 540,000 IU boost of vitamin D3 or matched placebo within 12 hours of the decision for ICU admission. At 90 days, mortality rates were 23.5% in the vitamin D group and 20.6% in the placebo group. “There were no clinically important differences between the groups with respect to secondary clinical, physiological, or safety endpoints,” write the study authors. “The severity of vitamin D deficiency at baseline did not affect the association between the treatment assignment and mortality.” It has been suggested that vitamin D did not improve outcomes because a maintenance dose was not administered after the initial boost. The ongoing VITDALIZE trial is currently assessing this.