A Genome Epidemiological Study of SARS-CoV-2 Introduction into Japan
Tsuyoshi Sekizuka, Kentaro Itokawa, Masanori Hashino, Tetsuro Kawano-Sugaya, Rina Tanaka, Koji Yatsu, Asami Ohnishi, Keiko Goto, Hiroyuki Tsukagoshi, Hayato Ehara, Kenji Sadamasu, Masakatsu Taira, Shinichiro Shibata, Ryohei Nomoto, Satoshi Hiroi, Miho Toho, Tomoe Shimada, Tamano Matsui, Tomimasa Sunagawa, Hajime Kamiya, Yuichiro Yahata, Takuya Yamagishi, Motoi Suzuki, Takaji Wakita, Makoto Kuroda
Abstract
This study aimed to evaluate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome sequences from COVID-19 cases and to characterize their genealogical networks to demonstrate possible routes of spread in Japan. We found that there were at least two distinct SARS-CoV-2 introductions into Japan, initially from China and subsequently from other countries, including Europe. Our findings can help understand how SARS-CoV-2 entered Japan and contribute to increased knowledge of SARS-CoV-2 in Asia and its association with implemented stay-at-home/shelter-in-place/self-restraint/lockdown measures. This study suggested that it is necessary to formulate a more efficient containment strategy using real-time genome surveillance to support epidemiological field investigations in order to highlight potential infection linkages and mitigate the next wave of COVID-19 in Japan.