Virological features and pathogenicity of SARS-CoV-2 Omicron BA.2
Jasper Fuk‐Woo Chan, Bingjie Hu, Yue Chai, Huiping Shuai, Huan Liu, Jialu Shi, Yuanchen Liu, Chaemin Yoon, Jinjin Zhang, Jingchu Hu, Yuxin Hou, Xiner Huang, Terrence Tsz‐Tai Yuen, Tianrenzheng Zhu, Wen‐Jun Li, Jian‐Piao Cai, Cuiting Luo, Cyril Chik‐Yan Yip, Jinxia Zhang, Jie Zhou, Shuofeng Yuan, Bao‐Zhong Zhang, Jian‐Dong Huang, Kelvin Kai‐Wang To, Kwok‐Yung Yuen, Hin Chu
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.2 was a dominant circulating SARS-CoV-2 variant worldwide. Recent reports hint that BA.2 is similarly potent regarding antibody evasion but may be more transmissible than BA.1. The pathogenicity of BA.2 remains unclear and is of critical public health significance. Here we investigated the virological features and pathogenicity of BA.2 with in vitro and in vivo models. We show that BA.2 is less dependent on transmembrane protease serine 2 (TMPRSS2) for virus entry in comparison with BA.1 in vitro. In K18-hACE2 mice, BA.2 replicates more efficiently than BA.1 in the nasal turbinates and replicates marginally less efficiently in the lungs, leading to decreased body weight loss and improved survival. Our study indicates that BA.2 is similarly attenuated in lungs compared with BA.1 but is potentially more transmissible because of its better replication at the nasal turbinates.