A simulation of geographic distribution for the emergence of consequential SARS-CoV-2 variant lineages

The coronavirus disease 2019 (COVID-19) pandemic has been facilitated by the intermittent emergence of consequential variant strains. This study evaluated the geographic disproportionality in the detection of consequential variant lineages across countries. As of November 2021, a total of 40 potentially consequential SARS-CoV-2 variant lineages have been identified. One-hundred repeated simulations that randomly produced consequential variants from overall COVID-19 cases worldwide were performed to evaluate the presence of geographical disproportion in the occurrence of consequential variant outbreaks. Both the total number of reported COVID-19 cases and the number of reported genome sequences in each country showed weak positive correlations with the number of detected consequential lineages in each country. The simulations suggest the presence of geographical disproportion in the occurrence of consequential variant outbreaks. Based on the random occurrence of consequential variants among COVID-19 cases, identified consequential variants occurred more often than expected in the United Kingdom and Africa, whereas they occurred less in other European countries and the Middle East. Simulations of the occurrence of consequential variants by assuming a random occurrence among all COVID-19 cases suggested the presence of biogeographic disproportion. Further studies enrolling unevaluated crucial biogeographical factors are needed to determine the factors underlying the suggested disproportionality.