Virological characteristics of the SARS-CoV-2 Omicron EG.5.1 variant

• DOI: 10.1101/2023.10.19.563209
• Publication Date: 2023-10-22T03:45:16Z
• Authors: Shuhei Tsujino; Sayaka Deguchi; Tomo Nomai; Miguel Padilla-Bl...; Arnon Plianchaisuk; Lei Wang; MST Monira Begum; Keiya Uriu; Keita Mizuma; Naganori Nao; Isshu Kojima; Tomoya Tsubo; Jingshu Li; Yasufumi Matsumura; Miki Nagao; Yoshitaka Oda; Masumi Tsuda; Yuki Anraku; Shunsuke Kita; Hisano Yajima; Kaori Sasaki-Tabata; Ziyi Guo; Alfredo A Hinay; Kumiko Yoshimatsu; Yuki Yamamoto; Tetsuharu Nagamoto; Hiroyuki Asakura; Mami Nagashima; Kenji Sadamasu; Kazuhisa Yoshimura; Hesham Nasser; Michael Jonathan; Olivia Putri; Yoonjin Kim; Luo Chen; Rigel Suzuki; Tomokazu Tamura; Katsumi Maenaka; ; Takashi Irie; Keita Matsuno; Shinya Tanaka; Jumpei Ito; Terumasa Ikeda; Kazuo Takayama; Jiri Zahradnik; Takao Hashiguchi; Takasuke Fukuhara; Kei Sato
• Keywords: Omicron; SARS-CoV-2; EG.5.1; Cryoelectron Microscopy; COVID-19; Antiviral Agents; ORF9b; SARS‐CoV‐2; Mice; COVID‐19; Spike Glycoprotein, Coronavirus; Chlorocebus aethiops; pathogenicity; Humans; Animals; Vero Cells; Phylogeny

Abstract In middle-late 2023, a sublineage of SARS-CoV-2 Omicron XBB, EG.5.1 (a progeny XBB.1.9.2), is spreading rapidly around the world. Here, we performed multiscale investigations to reveal virological features newly emerging variant. Our phylogenetic-epidemic dynamics modeling suggested that two hallmark substitutions EG.5.1, S:F456L and ORF9b:I5T, are critical increased viral fitness. Experimental addressing growth kinetics, sensitivity clinically available antivirals, fusogenicity pathogenicity comparable XBB.1.5. However, cryo-electron microscopy reveals structural difference between spike proteins We further assessed impact ORF9b:I5T on features, but it was almost negligible at least in our experimental setup. provide knowledge for understanding evolution trait pathogenic viruses human population.