Coast-to-coast spread of SARS-CoV-2 in the United States revealed by genomic epidemiology

Joseph R Fauver; Mary E. Petrone; Emma B Hodcroft; Kayoko Shioda; Hanna Y Ehrlich; Alexander G. Watts; Chantal B.F. Vogels; Anderson F. Brito; Tara Alpert; Anthony Muyombwe; Jafar Razeq; Randy Downing; Nagarjuna R. Cheemarla; Anne L Wyllie; Chaney C. Kalinich; Isabel Ott; Josh Quick; Nicholas J. Loman; Karla M. Neugebauer; Alexander L. Greninger; Keith R. Jerome; Pavitra Roychoundhury; Hong Xie; Lasata Shrestha; Meei-Li Huang; Virginia E. Pitzer; Akiko Iwasaki; Saad B. Omer; Kamran Khan; Isaac Bogoch; Richard A. Martinello; Ellen F. Foxman; Marie-Louise Landry; Richard A Neher; Albert I Ko; Nathan D. Grubaugh

A novel coronavirus, known as SARS-CoV-2, was identified as the cause of an outbreak of pneumonia in Wuhan, China, in December 2019 (Gorbalenya et al., 2020; Wu et al., 2020; Zhou et al., 2020) . Travel-associated cases of the disease COVID-19 were reported outside of China as early as January 13, 2020 and the virus has subsequently spread to nearly all nations (World Health Organization, 2020a , 2020b . The first detection of SARS-CoV-2 in the United States was a travel-associated case from Washington state on January 19, 2020 (Centers for Disease Control and Prevention, 2020a) . The majority of the early COVID-19 cases in the U.S. were either i) associated with travel to a "high-risk" country or ii) close contacts of previously identified cases, per the testing criteria adopted by the Centers for Disease Control and Prevention (CDC) (Centers for Disease Control and Prevention, 2020b) . In response to the risk of more travel-associated cases, the U.S. placed travel restrictions on multiple countries with SARS-CoV-2 transmission, including China on January 31, Iran on February 29, and Europe on March 11 (Taylor, 2020) . However, community transmission of SARS-CoV-2 was detected in the U.S. in late February when a California resident contracted the virus despite meeting neither testing criteria (Moon et al., 2020) .