Optimal timing for social distancing during an epidemic

Oscar Patterson-Lomba

is the (which was not peer-reviewed) The copyright holder for this preprint Optimal timing for peak reduction Figure 5 : Optimal t 0 to initiate social distancing if the goal is to reduce the epidemic peak, as a function of R 0 (x axis), reduction in transmissibility during social distancing r (y axis), and length of social distancing intervention (7, 14 and 30 days). As R 0 increases, the smaller the optimal time to initiate social distancing. For all simulations γ = 1/10. (6) shows that the optimal timing for social distancing decreases with R 0 in a quasi-exponential way, regardless of the epidemic containing strategy being employed. Interestingly, if the objective is to minimize final size, then the social distancing should start later compared to a social distancing strategy aimed at flattening the epidemic (either reducing or delaying the peak), with the differences decreasing as R 0 increases. For example, for an epidemic with R 0 = 1.5 (i.e., typical of a flu epidemic), the optimal social distance should be initiated 150 days after the start of the epidemic 1 if the goal is to minimize the final epidemic size, whereas if the goal is to delay or reduce the peak as much as possible, social distancing should start at about 120 days. 1 Strictly speaking, it is 150 days after 0.01% of the population has been infected, as I(0) = 0.01%.