Serological response after two doses of mRNA SARS-CoV-2 vaccination. (A) SARS-CoV-2 (Spike) antibody (AB) levels stratified for healthy controls (Ctrl) vs patients with multiple myeloma (MM) (≥8.52-11 360 BAU/mL considered as positive). The gray dashed line denotes the spike IgG cutoff of 143.5 BAU/mL corresponding to a WT neutralization titer ≥1:20 as determined by ROC analysis. WT neutralization titers stratified for healthy controls vs patients with MM (B) and healthy controls in comparison with different therapy status (none, on therapy, and on maintenance) of patients with MM (D). B.1.1.7 neutralization titers stratified for healthy controls vs patients with MM (C) and healthy controls in comparison with different therapy status of patients with MM (E). (F) Comparison of neutralization titers against WT and B.1.1.7. Gray lines in panels B-F denote a neutralization titer ≥1:20 corresponding to adequate protective neutralization capacity. P values are corrected for multiple testing with the Benjamini-Hochberg method.