a, Neutralization results for 20 convalescent plasma samples (P1–P20) against B.1.1.7, B.1.351 and wild-type viruses. The horizontal dotted lines on each graph indicate 50% and 0% neutralization. Reciprocal plasma dilutions are given as 1:X, in which X is the value on the x axis. Data are mean ± s.e.m. of technical triplicates. Neutralization by healthy donor plasma is shown in Extended Data Fig. 2b. b, Fold increase or decrease in neutralization ID50 of B.1.1.7 and B.1.351 viruses, B.1.1.7Δ8, B.1.351Δ9 and single-mutation pseudoviruses relative to the wild-type virus presented as a heat map in which darker colours indicate a greater change. Red, resistance >2.5-fold; green, sensitization >2.5-fold. c, Change in reciprocal plasma neutralization ID50 values of convalescent plasma against B.1.1.7, B.1.351, B.1.1.7Δ8 and B.1.351Δ9 relative to the wild-type virus. Mean fold changes in ID50 values relative to the wild-type virus are written above the P values. Statistical analysis was performed using a Wilcoxon matched-pairs signed-rank test. Two-tailed P values are reported.