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

Michael E. Hochberg

herd immunity threshold (20) . We find that although herd immunity is predicted to occur when 60 to 70% of the population have been infected and become immune (based on parameters in Table 1) , if left unchecked, then the virus will eventually infect approximately 90% of the population. Some countries with high numbers of infectious cases early in their outbreak may either not have the logistics for -or decide not to impose -suppression measures. For example, our analysis suggests that mitigation measures that lower â„›0 by 50% from 3.0 to 1.5 will still result in about 60% of the population eventually becoming infected. 5. Mitigation at or above C=1.0 extends the course of an outbreak (Figure 4) . Mitigation, even if less restrictive compared to suppression, has impacts on health services, society and the economy.