Antibody response rate and titers after a third vaccine dose in patients with CLL who failed to respond after the standard 2-dose BNT162b2 mRNA vaccination regimen. (A-B) Antibody response rate (%) and anti–SARS-CoV-2 antibody levels in patients with CLL shown for the entire cohort and according to the disease status: all CLL patients (n = 172); treatment naïve (n = 40); on-therapy (n = 100); and off-therapy (n = 32). (C) Response rate in patients with CLL treated with Bruton's tyrosine kinase inhibitor (BTKi; n = 59) and venetoclax (Ven) ± anti-CD20 antibody (n = 39). (D) Correlation between serological titers and neutralizing antibody levels following log transformation (n = 24), (Pearson's correlation coefficient r = 0.732; P < .001; r2 = 0.536). In an additional 30 patients, the anti–SARS-CoV-2 and neutralizing antibodies levels were negative and therefore were invalid for analysis.