This is a detailed in-vitro study of antibody resistance and viral receptor binding affinity of SARS-CoV-2 Omicron BQ.1, BQ.1.1, XBB, and XBB.1 subvariants, that are now prevalent and rapidly expanding globally. Sera from 5 cohorts (n=14-21 each) with the following histories were tested: 1) 3 doses of an original COVID-19 mRNA vaccine, 2) 4 doses of an original COVID-19 mRNA vaccine, 3) a fourth vaccination with a bivalent COVID-19 mRNA vaccine, 4) breakthrough BA.2 infection post-vaccination, and 5) breakthrough BA.4 or BA.5 infection. Results showed BQ.1.1 is approximately 6-fold more resistant to serum neutralization than its predecessor BA.5. XBB.1 is ∼63-fold more resistant to serum neutralization than its predecessor, or ∼49-fold more resistant than BA.4/5. SARS-CoV-2 breakthrough infection induced somewhat better antibody responses than vaccination. In addition, the clinically authorized monoclonal antibodies bebtelovimab and Evusheld could not neutralize BQ or XBB variants, leaving no effective preventative treatments for immunocompromised patients. The publication includes illustrative graphs, tables, and structural analysis. Analysis of cellular immunity and clinical studies are called for; however previous in-vitro studies have been predictive of in vivo outcomes.
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International Anesthesia Research Society
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