Reduced neutralizing capacity against SARS-CoV-2 variants of concern observed in a study of immune response against variants of concern in dialysis patients 4 months after SARS-CoV-2 mRNA vaccination. Neutralizing capacity of plasma IgG toward SARS-CoV-2 variants of concern Alpha (A), Beta (B), and Gamma and Delta (C) in the dialysis (blue circles, n = 76) and control (red circles, n = 23) groups 16 weeks after second vaccination with Pfizer-BioNTech vaccine BNT162b2 (https://www.pfizer.com). Neutralization capacity is displayed as ratio, where 1 indicates maximum neutralization and 0 no neutralization. Horizontal lines within boxes indicate medians; box tops and bottoms indicate the 25th and 75th percentiles; whiskers show the largest and smallest nonoutlier values. Outliers were determined by 1.5 times interquartile range. Statistical significance was calculated by 2-sided Mann–Whitney–U test. ACE2, angiotensin-converting enzyme 2; NS, not significant; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; T1, timepoint 1; T2, timepoint 2.