Corona virus diagram

Newly emerged Omicron sublineages more efficiently evade vaccine-elicited antibody protection

The new bivalent booster vaccine provides better protection against newly emerged Omicron sublianeages than previous monovalent COVID vaccines, according to new research from the University of Texas Medical Branch. Researchers also found that three of the new sublineages, BA.2.75.2, BQ.1.1, and XBB.1, exhibit the greatest evasion against vaccine-elicited neutralization and may become the new dominant strains.

“The findings may have a significant impact on vaccine strategy,” said Dr. Pei-Yong Shi, a corresponding author of the study and professor of the Department of Biochemistry & Molecular Biology at UTMB.

The newly emerged sublineages accumulated additional spike mutations that may affect vaccine effectiveness. The researchers reported neutralizing activities of three human serum panels with distinct vaccination and/or SARS-CoV-2 infection: one to three months after dose 4 of parental monovalent mRNA vaccine (post-dose-4), 1 month after a BA.5-bivalent-booster (BA.5-bivalent-booster), or 1 month after a BA.5-bivalent-booster with previous SARS-CoV-2 infection (BA.5-bivalent-booster-infection).

The study’s results support the following conclusions.

  • A BA.5-bivalent booster elicits better neutralization against the newly emerged Omicron sublineages than the parental mRNA vaccine. 
  • Individuals with SARS-CoV-2 infection history develop higher and broader neutralization against the ongoing Omicron sublineages after the BA.5-bivalent booster. 
  • Among tested Omicron sublineages, BA.2.75.2, BQ.1.1, and XBB.1 exhibit the greatest evasion against vaccine-elicited neutralization, suggesting the potential of these new sublineages to dethrone BA.5 as the dominant lineage in circulation.

“More human studies from different vaccine cohorts are needed to confirm this initial finding,” Shi said. “We also need real-world vaccine effectiveness results to validate the real impact of these laboratory findings.”

The study further underscores the importance of monitoring the emergence of new variants in circulation.

The researchers have submitted the study to bioRxiv and to peer review.