Dr. Campbell has been suggesting black people are impacted more due to vitamin D deficiency (dark skin inhibits vitamin D synthesis). His hypothesis is that having sufficient vitamin D gives a person a leg up on being capable of surviving the disease. Since it's summer for most people in the world, the hypothesis that vitamin D boosts the immune systems ability to fight the disease makes sense considering the increased spread and decreased mortality. If we begin to see increasing mortality in Australia and New Zealand that would further support the hypothesis. Of course, one could supplement with vitamin D as a precaution rather than spend time in the sun.