Yes. Most of the research I've seen (and I didn't go out of my way to do a proper review) seemed to indicate that the thinking was that Vitamin D was a prophyl

Yes. Most of the research I've seen (and I didn't go out of my way to do a proper review) seemed to indicate that the thinking was that Vitamin D was a prophylactic rather than a treatment. Or, perhaps more accurately, Vitamin D deficiency might be a risk factor for clinical infection. I'd be interested, as fraught as studies invoking race are at the moment, in statistics around clinically significant COVID infection categorized by ancestral regions, as Vitamin D deficiency in polar and temperate zones are so strongly correlated with skin colour.