Why is There Low Morbidity and Mortality of COVID-19 in Africa?

Abstract

Three months since the detection of the first COVID-19 case in Africa, almost all countries of the continent continued to report lower morbidity and mortality than the global trend, including Europe and North America. We reviewed the merits of various hypotheses advanced to explain this phenomenon, including low seeding rate, effective mitigation measures, population that is more youthful, favorable weather, and possible prior exposure to a cross-reactive virus. Having a youthful population and favorable weather appears compelling, particularly their combined effect; however, progression of the pandemic in the region and globally may dispel these in the coming months.

Figure 1.

COVID-19 epi curves for the United States and Italy (top) and Nigeria and Kenya (bottom). The x axis starts from 2 weeks after the first reported case in the United States (top) and Nigeria (bottom). The different y axis scales were used to allow visibility of the low number of cases in Nigeria and Kenya when compared with the United States and Italy. Data used to develop these curves were obtained from publicly available repositories and national health ministries as described in the Data Sources section.

Figure 2.

COVID-19 case fatality rate (CFR) for the United States, Italy, Nigeria, and Kenya. Data used to calculate the CFR were downloaded from publicly available repositories and national health ministries as described in the Data Sources section. The limitations to the CFR provided here include the fact that the number of cases (denominator) from each country is dependent on the strength of each country’s surveillance system and may underestimate the actual number of cases because of limitations in testing or those that do not seek medical care due to asymptomatic or mild infections.

Figure 3.

Average daily temperature between December and April over 10 years (2004–2013) in African countries. Data from Côte d’Ivoire were not available.