Chinese scientists have developed a mosaic nanoparticle candidate COVID-19 vaccine that can protect against the infections of COVID-19 variants.

Scientists from Sun Yat-sen University, the No. 1 Hospital Affiliated to Guangzhou Medical University, and the Guangdong Provincial Center for Disease Control and Prevention designed the quadrivalent mosaic nanoparticle vaccine comprising spike proteins from the SARS-CoV-2 prototype and three major variants including Alpha, Beta and Gamma variants.

The virus spike protein is known to play a critical role in viral attachment and fusion with the host cell, and therefore, the majority of antibodies that neutralize viral infection target the spike protein.

However, mutations from the virus variants located on the spike protein extensively lead to broad antibody resistance and immune escape from vaccinate-elicited sera, bringing additional uncertainty surrounding the efficacy of existing vaccines.

The nanoparticle is shown to have elicited equivalent or superior neutralizing antibodies against variant strains in mice and non-human primates with only a small reduction in neutralization titers against the ancestral strain, according to the study published recently in the journal Nature Communications.

They also tested the vaccine against Omicron and Lambda variants of the coronavirus. The two variants only slightly reduced the neutralization potency of sera induced by the vaccine, suggesting that the induced sera could elicit broadly protective antibody responses to circulating variants, according to the study.

The results provide a proof of principle for the development of multivalent vaccines against pandemic and potential pre-emergent SARS-CoV-2 variants, the researchers said.