This is most likely due to people with darker skin having lower vitamin D levels:
Probability of Vitamin D Deficiency by Body Weight and Race/Ethnicity
"Conclusions:
The effects of skin color and body weight on vitamin D status are large, both statistically and clinically. At typical target concentrations of deficiency (below 20 or below 30 ng/mL), those with darker skin colors or heavier body weights have a higher probability of being vitamin D deficient. Knowledge of these effects may facilitate the diagnosis of vitamin D deficiency."
There is a sad familiarity to the distribution of this disease, if one reviews the history of rickets:
Rickets before the discovery of vitamin D
"Progress in studies of the causes and treatment of rickets suddenly moved much faster, in the period 1917–1922. At the beginning of that time, Huldschinski33 advocated ultraviolet light treatment for rickets. At the same time, Hess34 showed that cod liver oil could prevent and cure rickets in Afro-American children in New York. ... On the veranda (Figure 3) one group was kept well covered while the other group of children, wearing remarkably little clothing, was exposed to sunlight. This second group got better. Thus it was shown that cod liver oil and exposure to sunlight both healed rickets. However, it was not clear at that time whether the effectiveness of cod liver oil was due to vitamin D or to vitamin A,... "
Unfortunately, once a minimal dose of Vitamin D was found to be enough to cure rickets, our government keepers pronounced any more to be probably "toxic" or at best unnecessary. It is time to consider whether we need "ancestral" levels of vitamin D.
There is an article on NIH by a Canadian physician (Dr. Gerry Schwalfenberg) who works in nursing homes. He has developed a protocol for reducing flu like illness among his patients. This should be tried against the corona virus in US nursing homes:
Vitamin D for influenza
"A colleague of mine and I have introduced vitamin D at doses that have achieved greater than 100 nmol/L in most of our patients for the past number of years, and we now see very few patients in our clinics with the flu or influenzalike illness. In those patients who do have influenza, we have treated them with the vitamin D hammer, as coined by my colleague. This is a 1-time 50 000 IU dose of vitamin D3 or 10 000 IU 3 times daily for 2 to 3 days. The results are dramatic, with complete resolution of symptoms in 48 to 72 hours. One-time doses of vitamin D at this level have been used safely and have never been shown to be toxic. We urgently need a study of this intervention. The cost of vitamin D is about a penny for 1000 IU, so this treatment costs less than a dollar."
There is a presentation by Dr. Robert P Heaney on the healthful effects of adequate vitamin D levels:
Vitamin D Sunshine Optimal Health: Putting it all Together
I drink milk and eat other products that claim to provide the Vitamin D I need. A certain demographic group feeds their babies and children sugar water that is called juice. Those children grow up, are obese, have diabetes, have high maternal and infant complications and death statistics and vulnerability to many diseases, of which COVID-19 is one.
It tracks back to the voluntary choice of sugar water over milk.