Marginal Value of Quarantine

Petrie, J. I.; Masel, J.

Different combinations of targeted quarantine and broad scale social distancing are equally capable of stemming the transmission of a virus like SARS-CoV-2. Finding the optimal balance between these policies can be operationalized by minimizing the total amount of social isolation needed to achieve a target reproductive number. This results in a risk threshold for triggering quarantine that depends strongly on disease prevalence in a population, suggesting that very different disease control policies should be used at different times or places. Very aggressive quarantine is warranted given low disease prevalence, while populations with a higher base rate of infection should rely more on broad social distancing. Total cost to a society can be greatly reduced given modestly more information about individual risk of infectiousness.