Neutralizing activity of BBIBP-CorV vaccine-elicited sera against multiple SARS-CoV-2 variants of concern

Abstract We assessed the safety and immunogenicity of an inactivated SARS-CoV-2 vaccine BBIBP-CorV, especially measured the resistance of four global variants of concern: Lineage B.1.1.7, Lineage B.1.351, Lineage P.1, and Lineage B.1.526 to neutralizing activity of vaccine-elicited sera. Among 1006 enrolled participants, no serious adverse event was reported within 28 days post-vaccination. Seroconversion of neutralizing antibodies was seen in 698 (91.84%) of 760 healthcare workers, and the geometric mean titres (GMTs) of neutralizing antibody titre was 62.68 (57.02–68.91) after the second immunization. We found that 57 (12.13%), 99 (20.97%), and 114 (24.26%) vaccine-elicited sera showed complete or partial loss of neutralizing activity against lineage B.1.1.7, lineage B.1.526, and lineage P.1, respectively, while 199 (42.34%) vaccine-elicited sera preserved neutralizing activity against lineage B.1.351, albeit at relatively low dilutions. These data indicated that humoral responses against SARS-CoV-2 could be effectively induced in vaccine recipients, although diminished neutralization potency against multiple variants was observed.