This is a peer-reviewed, randomized, controlled study of hospitalized Covid-19 patients. So it is an “RCT”. [Correction: no placebo was used. The intervention group received calcifediol and the control group did not. Both groups received BAT, best available treatment.] This is the type of study that the press and various online critics demand. Some persons unwisely reject all other types of studies, which is not reasonable or scientific. But this is the type of study we’ve been waiting for, to confirm the other 20 studies here.

The study took place in a university hospital setting: Reina Sofia University Hospital, in Cordoba, Spain. The 76 patients were all hospitalized for confirmed cases of Covid-19. So these are not the mild to moderate, stay-at-home types of patients. The intervention group was 50 patients and the control group was 26 patients.