Modeling the Comparative Impact of Individual Quarantine vs. Active Monitoring of Contacts for the Mitigation of COVID-19

Corey M Peak; Rebecca Kahn; Yonatan H Grad; Lauren M Childs; Ruoran Li; Marc Lipsitch; Caroline O Buckee

is the (which was not peer-reviewed) The copyright holder for this preprint . https://doi.org/10.1101/2020.03.05.20031088 doi: medRxiv preprint was 0.043, which translates to a need to quarantine a median of 23 truly infected R AM − R IQ = contacts to avert one infection beyond active monitoring alone. This value increases proportionally with the probability that a traced contact is not infected: 47 contacts need to be quarantined if 50% of contacts are infected; 468 if 5% of contacts are infected; and almost 54,000 if 0.04% of contacts are infected as observed for SARS control in Taiwan). 15 For the shorter serial interval scenario 1, the median incremental benefit of individual quarantine over active monitoring is much larger at 0.93, corresponding to a need to quarantine 1.1 infected contacts to prevent one secondary infection on average; though, if only 0.04% of traced contacts are infected, nearly 2,500 individuals need to be quarantined to prevent one secondary infection relative to active monitoring.