The geographic latitude-associated anti-COVID capacity index : an epidemiologic, demographic, and climate-based parameter negatively correlated with the COVID-19 death tolls

During the first two year of the Covid-19 pandemic, deaths tolls differed from a country to another. In a previous research work on 39 countries, we have found that some population’s characteristics were either negatively (birth rate/mortality rate, fertility rate) or positively (cancer score, Alzheimer disease score, percent of people above 65 years old, levels of alcohol intake) correlated with Covid-19 mortality. We also found that low levels of climate factors (average annual temperature, average hours of sunshine, average annual level of UV index) were positively correlated with Covid-19 deaths numbers as well. In the present study, we have developped an anti-Covid Capacity index that takes into account all the above mentioned parameters. The polynomial analysis of the anti-Covid Capacity and its corresponding geographic latitude of each country has generated a bell-shaped curve, with a high coefficient of determination (R2= 0.78). Lower anti-Covid capacity values were recorded in countries of low and high latitudes, respectively. Instead, plotting covid-19 deaths numbers against geographic latitude levels has generated an inverted bell-shaped curve, with higher deaths numbers at low and high latitudes, respectively. The analysis by a simple linear regression has shown that Covid-19 deaths numbers were significantly (p= 2,40 x 10-9) and negatively correlated to the anti-Covid Capacity index values. Our data demonstrate that the negative prepandemic human conditions, and the low scores of both annual temperature and UV index in many countries were the key factors behind high Covid-19 mortality, and they can be expressed as a simple index of anti-Covid capacity of a country that can predict the death-associated severity of Covid-19 disease, and thus, according to a country’s geographic latitude.