COVID-19 and Vitamin D: Could We Be Missing Something Simple? • Children’s Health Defense
There are studies suggesting that sufficient Vitamin D reduces the risk of acute respiratory infections. Also, the literature supports the importance of Vitamin D sufficiency in reducing morbidity and mortality in critical care settings. This is a sample of the literature.
A 2017 article in the BMJ states the following: “25 eligible randomized controlled trials (total 11 321 participants, aged 0 to 95 years) were identified… Vitamin D supplementation reduced the risk of acute respiratory tract infection among all participants (adjusted odds ratio 0.88, 95% confidence interval 0.81 to 0.96; P for heterogeneity <0.001).” The protective effects were greatest in those who were deficient (serum levels <25 nmol/L = 10ng/ml) and in those who took Vitamin D regularly (on a daily or weekly basis) compared to large bolus doses.
Another 2018 review of the literature specifically in intensive care settings suggests that the non-significant results in some large trials of Vitamin D supplementation are likely the result of including subjects who are Vitamin D sufficient in the trials and not excluding Vitamin D supplements in the control groups. The authors are clear that “three different meta-analyses confirm that patients with low vitamin D status have a longer ICU stay and increased morbidity and mortality” and that “this hormone plays an important pleiotropic (having more than one effect) role in the setting of critical illness and may support recovery from severe acute illness.”
A small 2019 Iranian study recommended larger follow-up studies after randomizing 44 mechanically ventilated adult patients to 300,000 IU of Vitamin D vs. placebo. The study found a significant reduction in mortality (61.1% vs. 36.3%) and a non-significant 10-day reduction in time on the ventilator.