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

In late December 2019, a cluster of cases of pneumonia of unknown aetiology in Wuhan city, Hubei province, China was reported by health authorities (Wuhan Municipal Health Commission 2019). A novel betacoronavirus, designated SARS-CoV-2, was identified as the causative agent (Wu et al. 2020) of the disease now known as COVID-19, with substantial humanto-human transmission (Lu et al. 2020) . To contain a growing epidemic, Chinese authorities implemented strict quarantine measures in Wuhan and surrounding areas in Hubei province. Significant delays in the global spread of the virus were achieved, but despite these measures, cases were exported to other countries. As of 9 March 2020, these numbered more than 100 countries, on all continents except Antarctica; the total number of confirmed infections exceeded 110,000 and there were nearly 4,000 deaths (Dong, Du, and Gardner 2020) . Although the majority of cases have occurred in China, major outbreaks have also been reported in Italy, South Korea, and Iran (World Health Organisation 2020a). Importantly, there is widespread local transmission in multiple countries outside China following independent importations of infection from visitors and returned travellers.