An article (see link below) https://clinmedjournals.org/article...ases-and-epidemiology-jide-3-030.php?jid=jide details a 2017 US study on how important vitamin D is in protecting us from viral respiratory tract infections. This study, based on 90 individuals found that ''infants with 25-OH vitamin D levels < 30 ng/mL suffered from more severe viral respiratory infections according to several objective measures when compared to those infants with sufficient levels'' and ''Pathophysiological evidence has been mounting that a sufficient level of 25-OH vitamin D is needed to protect against severe RSV and other viral respiratory tract infections.'' I am not an expert and maybe I'm stating the obvious, but could this partly explain the different pathway of the coronavirus in different parts of the world? Nearing the end of a cold, dark winter our levels of vitamin D are going to be at their lowest. If we mass administer this, it may counteract the fact that we are unable to go out in the sunshine right now. ''Conversion of vitamin D to the active form in humans begins with vitamin D3 production in the skin upon exposure to sunlight. Given the effects of vitamin D on immunity, it is plausible that the seasonality of ARI (acute respiratory infections) may be driven in part by periods of active vitamin D insufficiency during the winter and early spring months attributable to lower rates of skin conversion to D3.'' Thoughts ?