Analysis of SARS-CoV-2 genomes from across Africa reveals potentially clinically relevant mutations.

Abstract

SARS-CoV-2 is a betacoronavirus, the etiologic agent of the novel Coronavirus disease 2019 (COVID-19). The World Health Organization officially declared COVID-19 as a pandemic in March 2020 after the outbreak in Wuhan, China, in late 2019. Across the continents and specifically in Africa, all index cases were travel-related. Understanding how the viruss transportation across continents and different climatic conditions affect the genetic composition and the consequent effects on transmissibility, infectivity, and virulence of the virus is critical. Thus, it is crucial to compare COVID-19 genome sequences from the African continent with sequences from selected COVID-19 hotspots/countries in Asia, Europe, North and South America and Oceania. To identify possible distinguishing mutations in the African SARS-CoV-2 genomes compared to those from these selected countries, we conducted in silico analyses and comparisons. Complete African SARS-CoV-2 genomes deposited in GISAID and NCBI databases as of June 2020 were downloaded and aligned with genomes from Wuhan, China and other SARS-CoV-2 hotspots. Using phylogenetic analysis and amino acid sequence alignments of the spike and replicase (NSP12) proteins, we searched for possible vaccine coverage targets or potential therapeutic agents. Identity plots for the alignments were created with BioEdit software and the phylogenetic analyses with the MEGA X software. Our results showed mutations in the spike and replicate proteins of the SARS-Cov-2 virus. Phylogenetic tree analyses demonstrated variability across the various regions/countries in Africa as there were different clades in the viral proteins. However, a substantial proportion of these mutations (90%) were similar to those described in all the other settings, including the Wuhan strain. There were, however, novel mutations in the genomes of the circulating strains of the virus in African. To the best of our knowledge, this is the first study reporting these findings from Africa. However, these findings implications on symptomatic or asymptomatic manifestations, progression to severe disease and case fatality for those affected, and the cross efficacy of vaccines developed from other settings when applied in Africa are unknown.