Ksenia Safina, Elena Nabieva and Georgii Bazykin have co-authored a preprint “The rise and spread of the SARS-CoV-2 AY.122 lineage in Russia” recently released at medrXiv. The researchers aimed to study the emergence and spread of the Delta lineage in Russia. Using a phylogeographic approach, they inferred the import cases of Delta sublineages into Russia, and designed phylodynamic models to assess the rate of their spread. The authors showed that nearly the entire Delta epidemic in Russia has probably descended from a single import event despite genetic evidence of multiple Delta imports. Indeed, over 90% of Delta samples in Russia are characterized by the nsp2:K81N+ORF7a:P45L pair of mutations which is rare outside Russia, putting them in the AY.122 sublineage. The researchers concluded that the apartness of the genetic composition of the Delta epidemic in Russia makes Russia somewhat unusual, although not exceptional, among other countries. Full text of the preprint is available here.