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

Michael E. Hochberg

Here, we employ a simple epidemiological model to elucidate some of the basic parameters and processes that arbitrate short-term control measure outcomes. The model's intuitive results emphasize the necessity to adopt one or both of two strategies. 'Suppression measures' are engaged early and decisively to lower the reproduction number, â„›, below 1.0 and as close as possible to 0.0. When successful, this results in low, manageable numbers of infections, and can then be followed by a second strategy: 'Mitigation measures' that flatten the epidemic curve by maintaining the reproduction number to approximately 1.0. However, strategies need not follow this sequence. For those countries reacting very early in an outbreak, mitigation measures alone may be sufficient. For those that are late and/or unable to employ radical suppression measures, 'progressive mitigation' so as to lower â„› below 1.0 may be the only alternative.