What could explain the late emergence of COVID-19 in Africa?

Abstract

At the end of November 2019, a novel coronavirus responsible for respiratory tract infections emerged in China. Despite drastic containment measures, this virus, known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), spread in Asia and Europe. The pandemic is ongoing with a particular hotspot in southern Europe and America in spring 2020. Many studies predicted an epidemic in Africa similar to that currently seen in Europe and the USA. However, reported data do not confirm these predictions. Several hypotheses that could explain the later emergence and spread of the coronavirus disease 2019 (COVID-19) pandemic in African countries are being discussed, including the lack of health-care infrastructure capable of clinically detecting and confirming COVID-19 cases, the implementation of social distancing and hygiene, international air traffic flows, the climate, the relatively young and rural population, the genetic polymorphism of the angiotensin-converting enzyme 2 receptor, cross-immunity and the use of antimalarial drugs.

Introduction into the Marseille geographical area of a mild SARS-CoV-2 variant originating from sub-Saharan Africa: An investigational study

“…Several studies have described that clade 20A strains were imported to sub-Saharan Africa, particularly Senegal and Gambia, mostly by French travelers during phase 1 [ 8 ] , [ 9 ] , [ 10 ]. We assume that the ancestors of Marseille-1 variants originated in Senegal or Gambia, through progressive accumulation of mutations by clade 20A strains, and that their offspring were then brought to Maghreb and imported to Marseille by travelers as well as ferry sailors from Algeria and Tunisia ( Figure 1 ).…”

The SARS-CoV-2 pandemic: A syndemic perspective

“…Actually, the low intensity and lethality of the national epidemics in most African countries suggest hypothetical protective interactions of the high burden of tuberculosis (and/or BCG coverage) and tropical parasitic diseases, along with the lack of health-care infrastructure capable of clinically detecting and confirming COVID-19 cases, the implementation of social distancing and hygiene, international air traffic flows, the climate, the relatively young and rural population, the genetic polymorphism of the angiotensin-converting enzyme 2 receptor, cross-immunity and the use of antimalarial drugs [ [70] , [71] , [72] , [73] , [74] , [75] , [76] , [77] , [78] , [79] , [80] ]. However, the detection of a new variant of the SARS-CoV-2 in South Africa (variant 501Y·V2) in middle December 2020 with preliminary studies suggesting that the variant is associated with a higher viral load, which may suggest potential for increased transmissibility, might challenge the low transmissibility, low lethality trend observed so far in most African Countries [ 81 ].…”

Plasmodium falciparum malaria drives epigenetic reprogramming of human monocytes toward a regulatory phenotype

“…In much of Africa to date, the COVID-19 pandemic has not been as severe as predicted [41]. Although many environmental, genetic, sociocultural and institutional factors could contribute to lower COVID-19 morbidity and mortality in Africa compared to other regions [42], we speculate that COVID-19 severity in Africa may be mitigated by pre-existing differences in the immune system, including tolerized monocytes that produce lower levels of pro-inflammatory cytokines when activated.…”