On the benefits of flattening the curve: A perspective

The many variations on a graphic illustrating the impact of non-pharmaceutical measures to mitigate pandemic influenza that have appeared in recent news reports about COVID-19 suggest a need to better explain the mechanism by which social distancing reduces the spread of infectious diseases. And some reports understate one benefit of reducing the frequency or proximity of interpersonal encounters, a reduction in the total number of infections. In hopes that understanding will increase compliance, we describe how social distancing (a) reduces the peak incidence of infections, (b) delays the occurrence of this peak, and (c) reduces the total number of infections during epidemics. In view of the extraordinary efforts underway to identify existing medications that are active against SARS-CoV-2 and to develop new antiviral drugs, vaccines and antibody therapies, any of which may have community-level effects, we also describe how pharmaceutical interventions affect transmission. •Social distancing refers to non-pharmaceutical measures to mitigate pandemics.•These measures reduce the frequency or proximity of interpersonal encounters.•Their impact on daily and total numbers of new infections is commonly misrepresented.•We describe determinants of the magnitude and timing of the peak and the total number.•We also describe possible population-level effects of pharmaceutical interventions.