Is the Inversion in the Trend of the Lethality of the COVID-19 in the Two Hemispheres due to the Difference in Seasons and Weather?

Abstract

The climate has an influence on the COVID-19 virus lethality. The aim of this study is to verify if the summer weather coincided with the decrease of the Case Fatality Ratio (CFR) in Europe and if, on the contrary, an inverse trend was observed in Australia and New Zealand. To verify our hypothesis, we considered the largest European countries (Germany, UK, France, Italy, and Spain), plus Belgium and the Netherlands. Furthermore, we compared these countries with Australia and New Zealand. For each country considered, we have calculated the CFR from the beginning of the pandemic to May 6th and from May 6th to September 21st (late summer in Europe, late winter in the southern hemisphere). The CFRs were calculated from the John Hopkins University database. According to the results, in all European countries, a progressive decrease in CFR is observed. A diametrically opposite result is found in Australia where, on the contrary, the CFR is much higher at the end of September (at the end of winter) than on May 6th (mid-autumn), and the risk of dying if we count the infection is higher in September. In New Zealand, there are no statistically significant differences between the two surveys. The present study was based on public access macro data.