How Omicron dodges the immune system

Meriem Bekliz, first author, with a plaque-reduction neutralization assay used to determine the neutralizing capacity of antibodies. HUG-UNIGE - By comparing the neutralisation capacity induced by the different variants of SARS-CoV-2, a team from the UNIGE and the HUG reveals the exceptional capacity of Omicron to evade our immunity. The current wave of COVID-19 highlights a particularly high risk of reinfection by the Omicron variant of SARS-CoV-2. Why is this? A team from the Centre for Emerging Viral Diseases of the University of Geneva and of the Geneva University Hospital (HUG) analysed the antibody neutralisation capacity of 120 people infected with the original SARS-CoV-2 strain, or with one of its Alpha, Beta, Gamma, Delta, Zeta or Omicron (sub-variant BA.1) variants. And unlike its predecessors, Omicron appears to be able to evade the antibodies generated by all other variants. In vaccinated individuals, while the neutralisation capacity is also reduced, it remains far superior to natural immunity alone. This could explain why Omicron is responsible for a net increase in vaccine break-through infections, but not in hospitalisations.