Virological features and pathogenicity of SARS-CoV-2 Omicron BA.2

Abstract

SARS-CoV-2 Omicron BA.2 was a dominant circulating SARS-CoV-2 variant worldwide. Recent reports hinted that BA.2 is similarly potent in 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 further decreased on transmembrane protease, serine 2 (TMPRSS2) dependence for virus entry in comparison to BA.1 in vitro. In K18-hACE2 mice, BA.2 replicates more efficiently than BA.1 in the nasal turbinates while replicates marginally less efficiently in the lungs, leading to decreased body weight loss and improved survival. Overall, our study indicates that BA.2 is similarly attenuated in lungs when compared to BA.1 but is potentially more transmissible due to its better replication at the nasal turbinates.