Recombinant SARS-CoV-2 beta variant fusion protein vaccine + recombinant SARS-CoV-2 delta variant fusion protein vaccine

This is a combination of two recombinant subunit vaccines, each based on a fusion protein derived from the spike (S) glycoprotein of the SARS-CoV-2 virus—specifically, the Beta (B.1.351) and Delta (B.1.617.2) variants. These vaccines use engineered proteins that combine immunogenic regions of the viral spike proteins to elicit an immune response targeting both variants simultaneously[1][5]. The mechanism involves presenting key antigenic domains—such as receptor-binding domains (RBDs)—from each variant in a folded, stable form to stimulate neutralizing antibody production and cellular immunity against both Beta and Delta strains[1][7]. This approach aims to broaden protection by covering multiple variants with enhanced immune evasion or transmissibility properties[3][4][8]. Such vaccines are typically developed for prophylactic immunization against COVID-19.