Study Suggests Omicron Variant of SARS-CoV-2 More Infectious, Able to Dodge Neutralizing Antibodies

For a paper slated to appear in PNAS this week, investigators at the Gladstone Institutes, the University of California at Berkeley, and other centers explore infectivity patterns for the Omicron variant of SARS-CoV-2, along with host antibody responses to the mutated coronavirus. Along with virus-like particle (VLP)-based analyses of SARS-CoV-2 structural proteins in various SARS-CoV-2 variants, the team tracked antisera activity against such VLPs. Among other results, the authors saw lower-than-usual antisera efficacy against the Omicron variant using samples from dozens of vaccinated individuals or unvaccinated patients who survived COVID-19, though neutralizing antibodies against the variant could be incited by a third dose of the Pfizer vaccine. "Boosting increased neutralization titers against Omicron and restored neutralization in all subjects compared to one out of eight before boosting," they report. "Our results suggest that the rapid spread of Omicron is due to more efficient assembly, cell entry, and escape from antibody neutralization from existing vaccines or previous infection."