COVID-19’s epidemiological and demographic analysis in Africa

Abstract

Africa has 17% of the world population, but at the close of this analysis (12 October 2020), it had only 4.2% of cases and 3.5% of COVID-19 deaths in the world. Therefore, we can state that it is a continent that is little affected by COVID-19. All African countries fall within between latitude 37º 21' and 34° 50' S and about 80% of African territory is in the intertropical zone, having ultraviolet radiation throughout the year, which is an important source of vitamin D production by African populations. A demographic and epidemiological analysis is made of the 15 most populous countries in Africa, all of them with more than 25 million inhabitants. It has been found that, except for countries in North Africa and South Africa, the median age is around 20 years and about 40% of the population is under 15 years old. The percentage of the population aged 65 and over is small and, in many countries, is less than 5% of the population. These demographic characteristics can be shown to be favourable in relation to the COVID-19 pandemic. Population densities vary widely from Uganda's 222 inhabitants/km2 to Angola's 26 inhabitants/km2. The same is true of the percentage of urban population, which ranges from 21% in Ethiopia to 73% in Algeria. However, in Africa there are some of the megacities in the world, with high population densities, which theoretically enhances the transmissibility of the virus. An epidemiological analysis is made of the evolution of the number of cases, number of recovered cases, number of deaths and number of tests performed, per million inhabitants, in each of the 15 selected countries, and we illustrate the evolution with bar graphs of the daily records of cases and deaths and with curves of the respective averages of the last 7 days. It was found that, except for Angola and Morocco, the other countries analysed have already reached their peak and are in the resolution phase. It was also found that, with the exception of South Africa, where there was a cumulative of 11,840 cases and 305 deaths2 per million inhabitants, in the remaining countries, the epidemic has been benign, with the average number of cases (1,656) and deaths (37,8) per million inhabitants in these 15 most populous countries in Africa, respectively 3,2 times and 3,8 times less than the respective world averages. Only Egypt (5.8%), Angola and Algeria (both with 3.4%) have a case fatality rate above the world average. All other countries have case fatality rates below the world average, some of them among the lowest in the world. The authors analyse the various factors that may contribute to this benignity of the COVID-19 pandemic in Africa and noted that, until the period covered by our analysis the countries with the highest median age and with the highest percentage of population aged 65 and over are the countries most affected by the pandemic, but concluded that these statistical findings do not explain everything. The authors are aware of speculation that, in Africa, testing rates would be very low and that official statistics would therefore not be credible, but after a detailed analysis they concluded that it is clear that the benignity of the epidemic in Africa cannot be attributed to the fallacious argument of the "weak" testing index. The authors also analysed the population density and socioeconomic characteristics of African populations and concluded that these are conditions that, theoretically, would be highly favourable to the spread of COVID-19, which made the world fear an enormous health catastrophe in Africa. However, until the reference date of the data in this publication (12 October 2020), the numbers prove that it did not occur and therefore explanations need to be sought. We consider it neither credible nor sensible to admit that the benignity of the pandemic in Africa may be due to the circulation of less virulent strains of SARS-CoV-2 than those existing in circulation in the rest of the world. Nor do the authors attach great importance to the differences between various countries regarding the implementation of measures to prevent the epidemic, since statistical data show that countries that have not taken coercive measures are not more affected by the pandemic than those that have taken more stringent measures. In the African context, the existence of abundant ultraviolet radiation is especially important because it ensures the natural production of vitamin D, whose anti-inflammatory effects and consequently its protective effect, in relation to the lethality by COVID-19, are largely proven. Finally, the authors analyse in detail the immune status of African populations and consider that this is where the explanation for the benignity of the pandemic in Africa must be found.