SARS CoV-2 Escape Variants Exhibit Differential Infectivity and Neutralization Sensitivity to Convalescent or Post-Vaccination Sera

Towards eradicating COVID19, developing vaccines that induce high levels of neutralizing antibodies is a main goal. As counter measurements, viral escape mutants rapidly emerge and potentially compromise vaccine efficiency. Herein we monitored ability of convalescent or Pfizer-BTN162b2 post-vaccinated sera to neutralize wide-type SARS-CoV2 or its UK-B.1.1.7 and SA-B.1.351 variants. Relative to convalescent sera, post-vaccination sera exhibited higher levels of neutralizing antibodies against wild-type or mutated viruses. However, while SARS-CoV2 wild-type and UK-N501Y were similarly neutralized by tested sera, the SA-N501Y/K417N/E484K variant moderately escaped neutralization. Significant contribution to infectivity and sensitivity to neutralization was attributed to each of the variants and their single or combined mutations, highlighting alternative mechanisms by which prevalent variants with either N501Y or E484K/K417N mutations spread. Our study validates the clinical significance of currently administered vaccines, but emphasizes that their efficacy may be compromised by circulated variants, urging the development of new ones with broader neutralization functions. Funding Statement: This work was supported by the Israeli Mistry of Science and Technology (MOST; grant #3-16897) and the Israel Science Foundation (ISF; Research Grant Application no. 755/17). Declaration of Interests: The authors have no conflicts of interest to declare. Ethics Approval Statement: The study was conducted in compliance with the ethical principles of the Declaration of Helsinki and approved by the intuitional ethics committee.