Molecular mechanisms responsible for SARS-CoV-2 antibody waning and vaccine escape in Omicron sublineages BA.4 and BA.5.

Mutations in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome continue to threaten the global landscape of the coronavirus disease 2019 (COVID-19) pandemic. The Omicron variant (B.1.1.529) rapidly displaced previous 'variants of concern' (VoC) in 2021 due to its high rate of transmissibility and multitude of mutations. This global influx of infections saturated healthcare systems, overwhelmed testing capacity and case reporting, and increased the COVID-19 death toll. Global health leaders are now being faced with the most transmissible COVID-19 variants yet, the Omicron sublineages BA.4 and BA.5, which contain additional spike protein (S) mutations from previous Omicron and VoC serotypes. With universally observed antibody waning, increasing vaccine-variant mismatch, and resuming international travel, the stage is set for unprecedented levels of breakthrough infections and superspreading events. In this paper, we raise awareness to these novel variants and provide context for the high likelihood of an upcoming wave of infection capable of inflicting significant disease burden on a global scale.