Neutralizing antibody response to XBB.1.5, BA.2.86, FL.1.5.1, and JN.1 six months after the BNT162b2 bivalent booster

Objectives: An increase evasion of the SARS-CoV-2 virus toward vaccination strategies and natural immunity has been rapidly described notably because of the mutations in the spike receptor binding domain and the N-terminal domain. Methods: Participants of the CRO-VAX HCP study who received the bivalent booster were followed up at 6 months. A pseudovirus‐neutralization test was used to assess the neutralization potency of antibodies against D614G, Delta, BA.1, BA.5, XBB.1.5, BA.2.86, FL.1.5.1, and JN-1. Results: The neutralizing capacity of antibodies against the Omicron variant or its subvariants was significantly reduced compared with D614G and Delta (P