Fig 1.

Remaining SARS-CoV-2 binding and neutralizing antibodies before receiving booster vaccines. (A) Anti-RBD binding antibodies before the third (first booster) or fourth (second booster) dose of mRNA vaccine by days after the previous vaccine. (B) Anti-S1 binding antibodies before the third (first booster) or fourth (second booster) dose of mRNA vaccine by days after the previous vaccine. (C) Anti-S2 binding antibodies before the third (first booster) or fourth (second booster) dose of mRNA vaccine by days after the previous vaccine. (D) Neutralizing antibodies before the third or fourth mRNA vaccine dose by days after the previous vaccine. The table at the bottom summarizes neutralizing and binding antibody levels and P-values between groups. Pre-3: prior to the third dose of the original mRNA vaccine. Pre-4: prior to the fourth dose of the bivalent mRNA vaccine. “Hybrid” denotes hybrid immunity due to the combination of vaccination and natural infection. “Vaccine-only” means the participants had no evidence of natural infection. IQR, interquartile range.