A distinct phylogenetic cluster of Monkeypox genomes suggests an early and cryptic spread of the virus

Since its first reports in humans in 1970, monkeypox has been predominantly restricted to countries in Africa where the disease is endemic. Early in 2022, a large number of cases of the disease were reported from Europe and other countries in patients with no history of travel to regions where monkeypox is endemic. Amid a rise in cases, the availability of genome sequences of monkeypox virus isolates in the public domain provides an opportunity to understand the transmission and evolution of the virus. Here, we describe a distinct phylogenetic cluster of monkeypox virus (lineage A.2) using genome sequences available on GISAID. Lineage A.2 currently encompasses 9 genome sequences from 6 viral isolates collected from 3 countries and is distinctly different from the predominant lineage B.1 which is linked to the large European outbreak.