Immunogenicity and Safety of Beta Adjuvanted Recombinant Booster Vaccine (preprint)

ABSTRACT

Background. Variant-adaptated vaccines against coronavirus disease 2019 (COVID-19) as boosters are needed to increase a broader protection against SARS CoV-2 variants. New adjuvanted recombinant protein vaccines as heterologous boosters could maximize the response. Methods. In this randomized, single-blinded, multicenter trial, adults who had received two doses of Pfizer-BioNTech mRNA vaccine (BNT162b2) 3 to7 months before were randomly assigned to receive a boost of BNT162b2, Sanofi/GSK SARS-CoV-2 adjuvanted recombinant protein MV D614 (monovalent parental formulation) or SARS-CoV-2 adjuvanted recombinant protein MV B.1.351 vaccine (monovalent Beta formulation). The primary endpoint was the percentage of subjects with a [≥] 10-fold increase in neutralizing antibody titers for the Wuhan (D614) and B.1.351 (Beta) SARS-CoV-2 viral strains between day 0 and day 15. Findings. The percentages of participants whose neutralizing antibody titers against the Wuhan (D614) SARS-CoV-2 strain increased by a factor [≥]10 between day 0 and day 15 was 55.3% (95% CI 43.4-66.7) in MV D614 group (n=76), 76.1% (64.5-85.4) in MV B.1.351 (Beta) group (n=71) and 63.2% (51.3-73.9) in BNT162b2 group (n=76). These percentages were 44.7% (33.3-56.6), 84.5% (74.0-92.0) and 51.3% (39.6-63.0) for the B.1.351 (Beta) viral strain, respectively. Higher neutralizing antibodies rates against Delta and Omicron BA.1 variants were also elicited after Sanofi/GSK MV Beta vaccine compared to the other vaccines. Comparable reactogenicity profile was observed with the three vaccines. Interpretation. Heterologous boosting with the Sanofi/GSK Beta formulation vaccine resulted in a higher neutralizing antibody response against Beta variant but also the original strain and Delta and Omicron BA.1 variants, compared with mRNA BNT162b2 vaccine or the Sanofi/GSK MVD614 formulation. New vaccines containing Beta spike protein may represent an interesting strategy for broader protection against SARS CoV-2 variants.