titers for each serum sample. (A) Heat map of ID50 titers clustered by the viral phylogeny. The percentages below the heat map indicate the percentage of panel viruses that were neutralized (ID50 > 20) by the antibodies in each serum. (B) Histograms of the natural logarithm of ID50 titer. The distribution for CAP256 was notably different from that of the other sera.