Safety and Immunogenicity of a Bivalent SARS-CoV-2 Recombinant Protein Vaccine, SCTV01C in Unvaccinated Adults: A Randomized, Double-Blinded, Placebo-Controlled, Phase I Clinical Trial

In this journal, Liu and colleagues showed the potential efficacy of a recombinant protein vaccine for COVID-19 as a boost strategy.1 However, the rapid emergence of immune-evasive SARS-CoV-2 variants, especially the Omicron sub-variants, called for development of vaccines with cross-protection to a broad-spectrum of variants. SCTV01C is a recombinant bivalent vaccine comprised of trimeric spike extracellular domain (S-ECD) of SARS-CoV-2 variants Alpha (B.1.1.7) and Beta (B.1.351), and adjuvanted with SCT-VA02B, a squalene-based oil-in-water emulsion.