Huber, Colleen. The Defeat of COVID: 500+ medical studies show what works & what doesn’t (p. 58).
It would be quite difficult for a person with adequate serum vitamin D levels to die of COVID-19. How difficult is it?
Mayo Clinic found “Among patients admitted with laboratory-confirmed COVID-19, 25 (OH) D levels were inversely associated with in-hospital mortality and the need for invasive mechanical ventilation.” In this study of 120 already severe cases of COVID-19 in Algeria, it was also found that those with the lowest vitamin D levels were the most likely to die with a COVID-19 diagnosis. …
Considering that even among those with diagnosis of severe COVID-19 illness, represented in the above graph, only 10% of those with the modest vitamin D level of > 30 ng/ml died with a COVID-19 diagnosis, and the other 90% survived, then it is exceedingly difficult to die of COVID-19 with adequate vitamin D levels. Studies from all over the world show significantly and overwhelmingly lower rates of death in COVID-19 patients with adequate vitamin D levels. Here is a visual representation….
A diagnosis of COVID-19, currently defined by governments and media as a “case,” whether sick or well, is already shown in the studies above to be rare with adequate vitamin D levels.    Symptomatic expression of COVID-19 is still less likely with adequate Vitamin D levels. Hospitalization and mortality with COVID-19 patients has been found to be significantly lower among those with adequate serum vitamin D levels.   Each of these studies examined different serum levels of vitamin D among people in different parts of the world, with varying access to sunlight, with or without dosing of vitamin D, and with varying intervals of dosing. The data taken together, however, make a strong case for the difficulty of actually dying of COVID-19 while maintaining adequate vitamin D levels. The serum levels observed in the studies cited herein rarely reached into >70 ng/ml. The likelihood of dying from COVID-19 while maintaining vitamin D levels above this level seems to be vanishingly small if not impossible.