A CHINESE research team adopted a new strategy to design a new COVID-19 vaccine that has proved to be highly effective in mice and macaques against infections by Delta and Omicron variants.

The team that recently published its latest paper entitled “Protective prototype-Beta and Delta-Omicron chimeric RBD-dimer vaccines against SARS-CoV-2,” in Cell, a world top-ranking biology journal, was led by Gao Fu, director of the Chinese Center for Disease Control and Prevention, Wang Peiyi, a professor at the Southern University of Science and Technology (SUSTech), and Dai Lianpan, a researcher at the Chinese Academy of Sciences.

The researchers previously developed the protein subunit vaccine ZF2001 based on dimeric receptor-binding domain (RBD) of the prototype SARS-CoV-2 virus. In the latest study, the team developed a chimeric RBD-dimer vaccine approach to adapt to SARS-CoV-2 variants.

A prototype-Beta chimeric RBD-dimer was first designed to adapt to the resistant Beta variant. Compared with its homotypic forms, the chimeric vaccine elicited broader sera neutralization of variants and conferred better protection in mice. The chimeric vaccine’s protection was further verified in macaques, according to the researchers.

This approach was generalized to develop a Delta-Omicron chimeric RBD-dimer to adapt to the current prevalent variants. The vaccine conferred better protection against either Delta or Omicron SARS-CoV-2 in mice.

As breakthrough infections by COVID-19 variants become the global challenge for pandemic control, the chimeric approach is applicable for rapid immunogen updating. The data supported the use of variant-adapted multivalent vaccine against circulating and emerging variants, the researchers said.

Previously, ZF2001, the world’s first approved COVID-19 protein subunit vaccine, was developed and produced from a predesign concept developed by Gao’s team and approved for emergency use in China, Uzbekistan, Indonesia and Colombia. (Han Ximin)