World-wide tracking of major SARS-CoV-2 genome haplotypes in sequences of June 1 to November 15, 2020 and discovery of rapid expansion of a new haplotype

Abstract

Earlier, 13 haplotype groups defined by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome sequence variations were identified in 2790 sequences available in March 2020. Also, 23403A>G that causes p. Asp614Gly in the spike protein and is one of the defining variations of the haplotype group H1, was becoming increasingly prevalent. As a follow-up, 74922 SARS-CoV-2 sequences retrieved from individuals infected in June 1 to November 15 were analyzed. Consistent with the reports on 23403A>G, H1 haplotype frequency increased world-wide; among August to November sequences, only 0.3% were associated with non-H1 haplotypes. This finding prompted assessment of H1 sub-haplotypes among the sequences of the later stage of the coronavirus disease 2019 pandemic. The distribution of the sub-haplotypes differed in different regions, but 98.4% of the sequences were associated with five H1 sub-haplotypes. One of these had not been previously observed and had emerged in Europe by June 2020. The most important finding of the present study is identification of this new sub-haplotype (H1r) and finding evidence that suggest it may have a high potential for expansion. Its frequency had reached 10%–90% in various countries/territories of Europe by the end of September. The new sub-haplotype is defined by seven sequence variations, one of which causes Ala222Val in the spike protein.