Figure 11.

Panel (A) shows for each age class, the days elapsed from infection until the viral load starts to decrease. This is indicated as $t^{V_{max}}={\max }_t\left\{V\left(t\right)\right\}$since it means the distribution of the time when the antigen reaches the peak. It is a measure of how the immune defenses are mobilized, hence its speed. Panel (B) shows the corresponding distribution of $t_{\theta }={\min }_t\left\{V\left(t\right)\le \theta \right\}$namely the time it takes for the immune response to bring the viral load to fall below θ. It is a measure of the efficiency of the immune response in clearing the infection.