Delineating antibody escape from Omicron variants

SARS-CoV-2-neutralizing antibodies play a critical role for protection and treatment of COVID-19. Viral antibody evasion therefore threatens essential prophylactic and therapeutic measures. The high number of mutations in the Omicron BA.1 sublineage results in markedly reduced neutralization susceptibility. Consistently, Omicron is associated with lower vaccine effectiveness and a high re-infection rate. Notably, newly emerging Omicron sublineages (BA.1.1, BA.2) have rapidly become dominant. Here, we determine polyclonal serum activity against BA.1, BA.1.1 and BA.2 in 50 convalescent or vaccinated individuals as well as delineate antibody sensitivities on a monoclonal level using 163 antibodies. Our study reveals a significant but comparable reduction of serum activity against Omicron sublineages which markedly increases after booster immunization. However, notable differences in sensitivity to individual antibodies demonstrate distinct escape patterns of BA.1 and BA.2 that also affect antibodies in clinical use. The results have strong implications for vaccination strategies and antibody use in prophylaxis and therapy. ### Competing Interest Statement H.G., K.V., M.Z., C.K., and F. Klein are listed as inventors on patent applications on SARS-CoV-2-neutralizing antibodies encompassing aspects of this work filed by the University of Cologne.