Abstract
Large-scale populations in the world have been vaccinated with COVID-19 vaccines, however, breakthrough infections of SARS-CoV-2 are still growing rapidly due to the emergence of immune-evasive variants, especially Omicron. It is urgent to develop effective broad-spectrum vaccines to better control the pandemic of these variants. Here, we present a mosaic-type trimeric form of spike receptor-binding domain (mos-tri-RBD) as a broad-spectrum vaccine candidate, which carries the key mutations from Omicron and other circulating variants. Tests in rats showed that the designed mos-tri-RBD, whether used alone or as a booster shot, elicited potent cross-neutralizing antibodies against not only Omicron but also other immune-evasive variants. Neutralizing antibody titers induced by mos-tri-RBD were substantially higher than those elicited by homo-tri-RBD (containing homologous RBDs from prototype strain) or the inactivated vaccine BBIBP-CorV. Our study indicates that mos-tri-RBD is highly immunogenic, which may serve as a broad-spectrum vaccine candidate in combating SARS-CoV-2 variants including Omicron.
Competing Interest Statement
JingZ., Z.B.H., Y.L., X.F.Z., Y.Q.J., L.F.D., S.S., J.W.H., Z.H.L., Z.M.L., Y.N.H., N.L., F.J.S., J.J.W., X.Z., X.Y.L., X.L., J.G.S., and Q.M.L. are employees of National Vaccine and Serum Institute (NVSI). H.W. and JinZ. are employees of Beijing Institute of Biological Products Company Limited. Q.M.L., Y.L., JingZ., J.G.S., J.W.H., Z.B.H., X.F.Z., Y.Q.J., Z.M.L., L.F.D., Z.H.L., S.S., Y.N.H., N.L., and F.J.S. are listed as inventors of the pending patent application for the mos-tri-RBD vaccine (Application number: 202210083654.X). All other authors declare they have no competing interests.