Antigenic characterization of SARS-CoV-2 Omicron subvariants XBB.1.5, BQ.1, BQ.1.1, BF.7 and BA.2.75.2
Airu Zhu, Peilan Wei, Miao Man, Xuesong Liu, Tianxing Ji, Jiantao Chen, Canjie Chen, Jiandong Huo, Yanqun Wang, Jincun Zhao
Abstract
Recently, a number of new Omicron subvariants related to BA.4/5 and BA.2.75 have emerged and shown remarkable antibody evasion capacities, in particular BF.7, BQ.1, BQ.1.1, BA.2.75.2, XBB and XBB.1.5. 1 Unsurprisingly, these new subvariants are quickly gaining prevalence worldwide. In fact, some of them have outcompeted BA.5 in the USA according to CDC’s national genomic surveillance data in which, as of 6 th February 2023, XBB.1.5, BQ.1.1, BQ.1, XBB and BF.7 have achieved a dominance of 66.4%, 19.9%, 7.3%, 2.3% and 0.5% in the USA, as compared to 0.5% for BA.5. In this report, using plasma samples collected from individuals following different vaccination strategies and COVID-19 convalescent donors, we performed pseudoviral neutralization assays to confirm severe reductions in neutralization titers against BF.7, BQ.1, BQ.1.1, BA.2.75.2, XBB and XBB.1.5 in comparison to other Omicron sub-lineages. XBB and XBB.1.5 were shown to be remarkably resistant to plasma neutralization in all tested cohorts. By comparing the differential neutralization profiles, we found that a heterologous booster with an aerosolized vaccine following 2 doses of inactivated vaccine seemed to be superior to other vaccination strategies.