Fig. 5.

Each figure shows the prevalence with public health authority intervention, I _PHA(t), and with only the private mitigation effort, I _priv(t), for various β. The present value difference (PVD) in these curves is shown along with the intervention level of the public health authority. Positive PVD, corresponding to an early reduction in incidence that is not offset by the future “fatter” tail, is analogous to a tax on the cost of illness. Negative PVD was always found to include an early increase infection and is analogous to a subsidy on the cost of illness. The magnitude of intervention is directly related to the magnitude of the PVD.