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