New vaccines development


The emergence of variants with the ability to evade the immune system is driving a search for new development
strategies and expanding the range of viral epitopes, which the new vaccines are designed to address. The first
generation of vaccines targeted the virus's S protein, generating antibodies and T cells that recognize the receptorbinding
domain (RBD), to prevent the virus from entering host epithelial cells.

Some of the new approaches to the development of COVID-19 vaccines are now undergoing clinical evaluation. For
example, the RBD SARS-CoV-2 HBsAg VLP vaccine, which is in phase 1 and 2 clinical trials, is composed of protein
subunits, virus-like particles (VLP), which are composed of the receptor binding domain (RBD) of the SARS-CoV-2 S
protein, conjugated with hepatitis B surface antigen, obtained by recombinant DNA technology (rDNA).
Additional information on clinical trials of this vaccine is available at:

Another vaccine under development, based on VLP technology, called GBP-510, consists of computer-designed
protein nanoparticles obtained using rDNA technology. The size of the nanoparticles seems to favor immune transit
to the lymph nodes. This vaccine is in phase 1 and 2 clinical trials.

Additional information about the clinical trial is available at:

For multivalent vaccines, the California Institute of Technology, in the United States, has reported promising
immunogenicity data with an experimental multivalent vaccine using protein nanoparticles from different S protein
receptors (RBD) from various human and animal coronaviruses. This vaccine appears to cause cross-reactive immune
responses in mice, providing protection against strains that were not included in the experimental vaccine. In
addition, protection against the B.1.351 lineage strain is being evaluated, with protection studies to be conducted in
non-human primates

Source: Sheridan C. Innovators target vaccines for variants and shortages in global South. Nature Biotechnology.

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