Fig. 2: Mistiming an intervention reduces its effectiveness.

a–f Time courses of epidemics under optimal (a), fixed control (b), and full suppression (c), interventions that are possibly mistimed: a week late (dark lines), optimally timed (intermediate lines), and a week early (light lines). Dashed black line shows time course in the absence of intervention. d–f Time courses of epidemics with a sustained control that reduces the basic reproduction number \({{\mathcal{R}}}_{0}\) by 25%, combined with the effects of possibly mistimed optimal (d), fixed control (b), and full suppression (f) interventions, with line lightness as before. Dashed gray line shows time course with only sustained control and no additional intervention. g–i Effect of offset of intervention time t_i from optimal intervention time \({t}_{i}^{\,\text{opt}\,}\) on epidemic peak prevalence I^max without (solid lines) and with (dotted lines) sustained control for optimal (g), fixed control (h), and full suppression (i) interventions. Dashed black and gray lines show I^max in the absence of intervention, without and with sustained control, respectively. Plotted parameters: \({{\mathcal{R}}}_{0}=3\) and \(\gamma =\frac{1}{14}\) days⁻¹. See Table 1 for parameter justifications.