Figure. Reverse cumulative distribution (RCD) curves of enterovirus D68 (EV-D68) representing the distribution of neutralizing antibody titers against 3 EV-D68 viruses (clades B1, B2, and D) in serum samples obtained in 2017 from children <18 years of age in Kansas City, Missouri, USA, by patient age group. A) 6–35 months of age; B) 36–71 months of age; C) 72 months–10 years of age; D) 11–15 years of age; E) 16–18 years of age. A titer >3.0 log2 was considered positive for neutralizing antibodies. RCDs are curves for which each data point is the proportion of the population with a titer at least as high as the value on the x-axis. The calculated values for each area under curve (AUC) enable comparison of overall immune responses among age groups. Each panel shows 3 RCDs (1 for each virus). Panel A shows that the widest divergence of curves occurred among patients 6–35 months of age, who were born after the 2014 outbreak, suggesting less cross-neutralization among the 3 related viruses in this age group. RCDs become more convergent with each increasing age group. The largest AUCs in each age group are for the B1 predominant 2014 outbreak virus.