Researchers from University of Tsukuba and Institute of Science Tokyo have identified nonrandom patterns in the emergence of spike D614 reversions in publicly available SARS-CoV-2 genomic data. Analysis of publicly available sequences revealed numerous instances in which the spike D614G substitution, previously associated with increased transmissibility, reverted from G614 to the ancestral D614 residue, with these events predominantly occurring in the delta and omicron BA.2 lineages. The detected reversions also exhibited nonrandom patterns in temporal occurrence and geographic distribution.