Immunogenicity of bivalent versus monovalent mRNA booster vaccination among adult paramedics in Canada who had received three prior mRNA wild-type doses

• DOI: 10.1099/acmi.0.000791.v3
• Publication Date: 2025-01-13T16:17:05Z
• Authors: Michael Asamoah-B...; David M. Goldfarb; Iryna Kayda; Justin Yap; Tracy Kirkham; Mohammad Ehsanul ...; Paul Demers; Jeffrey M. Copp; Brian Grunau
• Keywords: Bivalent (engine); Booster dose

Introduction. Comparative immunogenicity from different mRNA booster vaccines (directed at WT, BA.1 or BA.4/5 antigens) remains unclear. Methods. We included blood samples adult paramedics who received three WT-directed plus a fourth dose of the following: (1) WT monovalent, (2) Moderna BA.1-WT bivalent (3) Pfizer vaccine. The primary outcome was angiotensin-converting enzyme 2 (ACE2) inhibition to antigen. used optimal pair matching (using age, sex-at-birth, preceding SARS-CoV-2 infection and vaccine-to-blood collection interval) create balanced groups individually compare each vaccine type other (overall, within subgroups defined by after combining cases). compared outcomes with Wilcoxon matched-pairs signed rank test. Results. Overall, 158 (mean age 45 years) were included. ACE2 higher for ( P =0.002); however, no difference detected between vs. BA.4/5. Among cases SARS-CoV-2, there between-group differences. without only BA.1>WT =0.003). combined had than Conclusion. Omicron-directed appear improve Omicron-specific immunogenicity; this appears limited SARS-CoV-2-naive individuals.