Pathogenicity, transmissibility, and fitness of SARS-CoV-2 Omicron in Syrian hamsters

Shuofeng Yuan, Zi Wei Ye, Ronghui Liang, Kaiming Tang, Anna Jinxia Zhang, Gang Lu, Chon Phin Ong, Vincent Kwok Man Poon, Chris Chung Sing Chan, Bobo Wing Yee Mok, Zhenzhi Qin, Yubin Xie, Allen Wing Ho Chu, Wan Mui Chan, Jonathan Daniel Ip, Haoran Sun, Jessica Oi Ling Tsang, Terrence Tsz Tai Yuen, Kenn Ka Heng Chik, Chris Chun Yiu ChanJian Piao Cai, Cuiting Luo, Lu Lu, Cyril Chik Yan Yip, Hin Chu, Kelvin Kai Wang To, Honglin Chen, Dong Yan Jin, Kwok Yung Yuen, Jasper Fuk Woo Chan

Research output: Contribution to journalArticlepeer-review

134 Citations (Scopus)

Abstract

The in vivo pathogenicity, transmissibility, and fitness of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron (B.1.1.529) variant are not well understood. We compared these virological attributes of this new variant of concern (VOC) with those of the Delta (B.1.617.2) variant in a Syrian hamster model of COVID-19. Omicron-infected hamsters lost significantly less body weight and exhibited reduced clinical scores, respiratory tract viral burdens, cytokine and chemokine dysregulation, and lung damage than Delta-infected hamsters. Both variants were highly transmissible through contact transmission. In noncontact transmission studies Omicron demonstrated similar or higher transmissibility than Delta. Delta outcompeted Omicron without selection pressure, but this scenario changed once immune selection pressure with neutralizing antibodies - active against Delta but poorly active against Omicron - was introduced. Next-generation vaccines and antivirals effective against this new VOC are therefore urgently needed.

Original languageEnglish
Pages (from-to)428-433
Number of pages6
JournalScience
Volume377
Issue number6604
DOIs
Publication statusPublished - Jul 22 2022
Externally publishedYes

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