The team used data from virus genomes sampled from across the world between 24 December 2019 and 4 March 2020. The research revealed three distinct “variants” of COVID-19, consisting of clusters of closely related lineages, which they label ‘A’, ‘B’ and ‘C’.
Forster and colleagues found that the closest type of COVID-19 to the one discovered in bats – type ‘A’, the “original human virus genome” – was present in Wuhan, but surprisingly was not the city’s predominant virus type.
Mutated versions of ‘A’ were seen in Americans reported to have lived in Wuhan, and a large number of A-type viruses were found in patients from the US and Australia.
The team used data from virus genomes sampled from across the world between 24 Dec ...
Wuhan’s major virus type, ‘B’, was prevalent in patients from across East Asia. However, the variant didn’t travel much beyond the region without further mutations – implying a "founder event" in Wuhan, or “resistance” against this type of COVID-19 outside East Asia, say researchers.
Variant ‘A’, most closely related to the virus found in both bats and pangolins, is described as “the root of the outbreak” by researchers. Type ‘B’ is derived from ‘A’, separated by two mutations, then ‘C’ is in turn a “daughter” of ‘B’.