Effect of adjuvanting RBD-dimer-based subunit COVID-19 vaccines with Sepivac SWE™.

Protein subunit vaccines have been widely used to combat infectious diseases, including the current COVID-19 pandemic. Adjuvants play the key role in shaping the quality and magnitude of the immune response to protein and inactivated vaccines. We previously developed a protein subunit COVID-19 vaccine, termed ZF2001, based on an aluminium hydroxide-adjuvanted tandem-repeat dimeric receptor-binding domain (RBD) of the viral spike (S) protein. Here, we described the use of a squalene-based oil-in-water adjuvant, Sepivac SWE™ (abbreviated to SWE), to further improve the immunogenicity of this RBD-dimer-based subunit vaccines. Compared with ZF2001, SWE adjuvant enhanced the antibody and CD4+ T-cell responses in mice with at least 10 fold of dose sparing compared with ZF2001 adjuvanted with aluminium hydroxide. SWE-adjuvanted vaccine protected mice against SARS-CoV-2 challenge. To ensure adequate protection against the currently circulating Omicron variant, we evaluated this adjuvant in combination with Delta-Omicron chimeric RBD-dimer. SWE significantly increased antibody responses compared with aluminium hydroxide adjuvant and afforded greater neutralization breadth. These data highlight the advantage of emulsion-based adjuvants to elevate the protective immune response of protein subunit COVID-19 vaccines.

Protocol for the clinical performance assessment of SARS - CoV - 2 antibody testing reagent

To date, the coronavirus disease 2019 (COVID-19) pandemic is impacting globally. COVID-19 is mainly diagnosed via viral nucleic acid testing, but with the disadvantages of unsatisfactory sensitivity and high requirements for expensive equipment and facility the operating settings. Compared with nucleic acid testing, antibody testing usually has advantages as wide popularization, convenient sample collection, easy to achieve high throughput. less workload, high reproducibility, and low cost, therefore it will be an efficient supplement for nucleic acid detection to confirm COVID-19. This protocol provided detailed design for the assessment of antibody testing reagent, including consideration for the study objectives, calculation of sample size, inclusion and exclusion criteria, blinding method, experimental specimen, ethical issues, study management and quality control, data management and statistical analysis. and results report and so on, aiming to assist the researchers to systematically assess the critical performance of antibody testing reagent prior to large-scale application of the antibody testing reagent, so that researchers could make reasonable choices among different antibody testing reagents according to their respective purposes.