Pfizer-BioNTech announced results from an analysis assessing the immune response induced by the Omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine (Pfizer-BioNTech COVID-19 vaccine, bivalent [original and Omicron BA.4/BA.5]) against newer Omicron sublineages, including BA.4.6, BA.2.75.2, BQ.1.1, and XBB.1.
The data from this analysis is posted on the preprint server, bioRxiv, and indicated that the companies’ bivalent vaccine elicits a better increase in neutralizing antibody titers than the companies’ original COVID-19 vaccine against these emerging Omicron sublineages. Based on these findings, the Omicron BA.4/BA.5-adapted bivalent booster may assist in providing enhanced protection against COVID-19 due to Omicron BA.4 and BA.5 sublineages as well as new sublineages that continue to increase in incidence.
Neutralization data were produced by means of a nonvalidated fluorescent focus reduction neutralization test 1 month after administration of a 30-mcg booster (fourth) dose of the companies’ Omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine or the original COVID-19 vaccine in adults aged 55 years and older (approximately 40/vaccine group). Sera were equally stratified by prior SARS-CoV-2 infection. The results revealed the bivalent vaccine booster elicited a greater rise in neutralizing antibody titers for all tested Omicron sublineages compared with the original vaccine, regardless of prior SARS-CoV-2 infection status.
Following a booster dose of the Omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine, neutralizing antibodies against BA.4.6 augmented 11.1-fold (95% CI: 7.1, 17.3), while neutralizing antibodies against BA.2.75.2, BQ.1.1, and XBB.1 increased by 6.7-fold (95% CI: 4.4,10.2), 8.7-fold (95% CI: 5.7, 13.3), and 4.8-fold (95% CI: 3.3, 6.9), respectively.
By comparison, the neutralizing antibody titers against BA.4.6, BA.2.75.2, BQ.1.1, and XBB.1 following a booster dose of the companies’ original COVID-19 vaccine augmented 2.3-fold (95% CI: 1.9, 2.8), 2.1-fold (95% CI: 1.7, 2.5), 1.8-fold, (95% CI: 1.6, 2.2), and 1.5-fold (95% CI: 1.3, 1.8), respectively.
Overall, the bivalent booster generated a greater increase in neutralizing antibodies against emerging Omicron sublineages than the original Pfizer-BioNTech COVID-19 vaccine. These results are comparable with recent clinical data showing the Omicron BA.4/BA.5-adapted bivalent booster induces a 13-fold increase in BA.4/BA.5 neutralizing titers from prebooster levels in individuals aged 55 years and older, resulting in a fourfold higher BA.4/BA.5 response than the companies’ original COVID-19 vaccine.
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Published December 6, 2022