Antibody and B‐Cell Responses to PHH‐1V81 XBB.1.16‐Adapted SARS‐CoV‐2 Booster Vaccination Are Associated With Variant Neutralization

Immune escape by SARS-CoV-2 emerging variants jeopardizes vaccine effectiveness, necessitating new immunization strategies. Here, we assessed the antibody B-cell response in 40 individuals receiving either the PHH-1V81 XBB.1.16- or BNT162b2 XBB.1.5-adapted vaccine boosters. Both immunizations significantly increased ancestral-reactive B cells cross-recognizing the vaccine variant. Notably, XBB.1.16 cross-reactive B cells were associated with neutralizing responses, reinforcing the potential of PHH-1V81 as a strong boosting candidate against emerging variants.