In the last post, we discovered an Upper Infection Limit for COVID-19. Its cases positively correlate to density (as expected) and per capita GDP (not expected). After Mike McRae wrote that “COVID-19 Deaths Are Being Linked to Vitamin D Deficiency (Health, May 1, 2020),” I decided to dig deeper.
I found COVID-19 has a Lower Infection Limit at work, too. Shown in white below, the line describing this threshold has an adjusted R^2 of 93.5% and a P-value of 3.05E-06, reflecting that it did not come about by chance. The difference in the countries that form each line is just as significant.
Excepting Qatar and the United States, all of the countries along the upper curve are European, and their southernmost extent is 37°55′ N (the southern tip of Italy). The nations forming the Lower Infection Limit are Asian or African, and, if we remove India and China, their northernmost point is 28°32’N (Myanmar), with most of their landmasses in the tropics.
Given the relative success of the tropical countries, should we increase sun exposure in northern climes? How does sun angle to the ground regulate Vitamin D uptake and Coronavirus inflection rates?