Vitamin D: The cheapest, easiest, safest armour against COVID-19

From a recent study in the Phillipines: The Vitamin D level was found to be lowest in critical cases and highest in mild cases (of Covid-19). Most of those infected had Vitamin D deficiency.

 

For each standard-deviation increase in serum 25-hydroxy-Vitamin D, the risk of a severe outcome was reduced eightfold, and the risk of a critical outcome was reduced 20-fold.
My noble friend Lord Ridley, reporting this result in The Times a couple of days ago, wrote: “Of 49 patients with mild symptoms … only two had low levels of vitamin D; of 104 patients with critical or severe symptoms, only four did not have low levels of vitamin D.”

It's appropriate to boost your defences.  The hydroxchlorquine/quercetin option to improve zinc uptake by cells in another example.  Avoiding a battle makes more sense than just relying on good medical aid in a war zone.