Optimal timing for social distancing during an epidemic

Oscar Patterson-Lomba

We investigated the idea of optimally timing the start of temporary social distancing measures to more effectively hinder the spread of an epidemic. We find that, for a given disease transmissibility, and social distancing transmission-reduction effectiveness and length, there exists an optimal time to initiate the social distancing intervention. Regardless of the criteria used to define "optimum" timing, let it be final epidemic size reduction, epidemic peak delay or epidemic peak reduction, the timing is closely related to R 0 , and not so much with T and r. Moreover, we find that the optimal time follows an approximate exponential decay relationship with R 0 , such that the higher the R 0 the sooner social distancing measures should be initiated.