Figure 1.

Effects of constant-strength and constant-speed intervention on infection kernels. Ebola-like gamma infection kernel (pre-intervention) $K_{\mathrm{pre}}(\tau )$ (mean: 16.2 days, CV: 0.58 and ${\mathcal{R}}_{\mathrm{pre}}$: 1.5) is shown in black [21]. The post-intervention kernel after applying each intervention strategy $K_{\mathrm{post}}(\tau )$ is shown in red. (a) The effect of a constant-strength intervention with θ = 1.5. A constant-strength intervention reduces the density by a constant proportion: $K_{\mathrm{post}}(\tau )=K_{\mathrm{pre}}(\tau )/\theta$; when the strength of intervention matches the strength of epidemic ($\theta ={\mathcal{R}}_{\mathrm{pre}}$), the resulting distribution is equivalent to the intrinsic generation-interval distribution ($K_{\mathrm{post}}(\tau )=g(\tau$)). (b) A constant-speed intervention with ϕ ≈ 0.0267/day is applied to the same kernel. A constant-speed intervention reduces the density exponentially: $K_{\mathrm{post}}(\tau )=K_{\mathrm{pre}}(\tau )\exp (-\varphi \tau )$; when the speed of intervention matches the speed of epidemic ($\varphi =r_{\mathrm{pre}}$), the resulting distribution is equivalent to the initial backward generation-interval distribution ($K_{\mathrm{post}}(\tau )=b(\tau$)). (Online version in colour.)