Fig. 1

Study design and longitudinal sample collection for XBB-containing vaccine booster cohorts. a Enrollment and demographics of the three cohorts receiving the Tri‑XBB.1.5 vaccine, Bi‑Omi‑XBB vaccine, and Tetra‑XBB.1 vaccine. Follow-ups were conducted at 21, 92, and 185 days post-booster vaccination to evaluate the durability of neutralizing antibodies and SARS-CoV-2 infections. b Timeline of booster vaccination and serum sample collection for the three cohorts. Longitudinal blood sampling for each cohort was conducted at baseline (day 0) and post-booster (days 21, 92, and 185). The Tri‑XBB.1.5 cohort maintained complete sample availability (n = 30 per time point), and the Bi‑Omi‑XBB and Tetra‑XBB.1 cohorts maintained complete sample (n = 30) availability at days 0, 21, and 92 but 28 on day 185 post-booter vaccination. The syringe indicates the administration of booster vaccination; the red raindrop represents blood collection. The days associated with vaccination and blood sampling are labeled below the corresponding time points, and the serum samples are labeled below the days