Figure 3

Absolute maximum number of daily SARS-CoV-2 deaths per million inhabitants for the 214 Countries (or territories) of our sample, versus the Solar UV Inactivation index Ξ on the Earth 3 weeks prior to the mortality peak. The Solar UV Inactivation Index Ξ is defined as the ratio of the SUVIP administered in 2 min to the Covid-19 lethal dose D63. (see “Methods”). Pink, green and yellow circles are Countries of the north hemisphere (α > 20 degrees: 103 Countries; N group), the equatorial strip (|α| ≤ 20 degrees: 93 Countries; T group), and the south hemisphere (α < −20 degrees: 18 Countries; S group), respectively. Grouping the data in either 5-degree-wide latitude bins (left onset) or 0.1-wide Ξ bins (right onset) greatly reduces the scatter present in the main plot, but also the degrees of freedom of the relations, thus yielding to higher (but still low) probabilities of chance correlation.