An emergent clade of SARS-CoV-2 linked to returned travellers from Iran

Eden, John-Sebastian; Rockett, Rebecca; Carter, Ian; Rahman, Hossinur; de Ligt, Joep; Hadfield, James; Storey, Matthew; Ren, Xiaoyun; Tulloch, Rachel; Basile, Kerri; Wells, Jessica; Byun, Roy; Gilroy, Nicky; O’Sullivan, Matthew V; Sintchenko, Vitali; Chen, Sharon C; Maddocks, Susan; Sorrell, Tania C; Holmes, Edward C; Dwyer, Dominic E; Kok, Jen

Although all known cases linked to Iran are contained in this clade, it is important to note the presence of two Chinese strains sampled during mid-January 2020 from Hubei and Shandong provinces. It is expected that further Chinese strains will be identified that fall in this clade, and across the entire phylogenetic diversity of SARS-CoV-2 as this is where the outbreak started, including likely for the outbreak in Iran itself. However, while we cannot completely discount that the cases in Australia and New Zealand came from other sources including China, our phylogenetic analyses, as well as epidemiological (recent travel to Iran) and clinical data (date of symptom onset), provide evidence that this clade of SARS-CoV-2 is directly linked to the Iranian epidemic, from where genomic data are currently lacking. Importantly, the seemingly multiple importations of very closely related viruses from Iran into Australia suggest that this diversity reflects the early stages of SARS-CoV-2 transmission within Iran.