Figure 2. A) Perspective surfaces of neutralizing antibody titer (dilution) based on the fitted linear mixed model in Table 5. The median age was 36 years for men (left panel) and for women (right panel). B) Cross-sectional curves of neutralizing antibody titer (dilution) extracted from panel A with duration of illness set at 10, 17, 24, and 31 days, respectively, for men (left panel) and women (right panel); the vertical lines mark peak titer times.