Limited Neutralization of Omicron by Antibodies from the BNT162b2 Vaccination against SARS-CoV-2

Since early December 2021, the omicron variant has posed additional challenges to the world-wide management of the SARS-CoV-2 pandemic. Immune evasion is a key factor for its increased transmissibility. While serological studies have measured levels of neutralizing antibodies in response to vaccines, our understanding of the humoral immune response to omicron on a single-antibody level is limited. Here, we characterize a set of BNT162b2 vaccine-derived antibodies for neutralization of omicron pseudovirus. We show that approximately 50% of neutralizing anti-RBD antibodies cross-neutralize omicron, albeit with lower potency than the original Wuhan-Hu1 strain. All investigated neutralizing anti-S2 antibodies cross-neutralize omicron, however all of them are less potent than anti-RBD antibodies. While additional booster immunizations of the current vaccine generate increased antibody levels and better protection, we anticipate that the second generation of vaccines will yield more high-affinity antibodies against omicron.