Importance of suppression and mitigation measures in managing COVID-19 outbreaks

Michael E. Hochberg

We observed that the attainment of herd immunity, whereby the rate of new infections is reduced below unity (when St/N<1.0-1.0/â„›), did not ensure the rapid end to an outbreak ( Fig. 2A) . Indeed, 'epidemic overshoot' (20) occurs in this simple model, for all â„›>1.0. Figure Finally, whereas mitigation measures result in fewer cases (Figs. 2, 3) , if â„›C>1.0, then they also lengthen the course of the epidemic (Figure 4 ). An epidemic with no mitigation (example shown here is â„›0 =3.0) is 95% complete 85 days after the 100 th case. In contrast, an outbreak coming closest to the mitigation target of a flat epidemic (â„›C =1.2) is 80% complete after 482 days and 95% at 585 days. The implications of long-term mitigation levels are discussed below. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.