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

As described previously, 6 two settings are defined with respect to the feasibility of interventions (Table 1) . A high feasibility setting, presented as the main results, is defined as one where 90% of contacts are traced and are put under either quarantine or active monitoring within half a day on average. Contacts under active monitoring are monitored twice per day on average. A contact under quarantine has infectiousness reduced by 75% until symptoms emerge and prompt isolation. When symptoms emerge in a contact under quarantine or active monitoring, they are isolated in a setting that reduces infectiousness by 90%. Assuming perfect intervention performance is not possible, the high feasibility parameters represent an upper-bound on the expected ability to implement interventions based on contact tracing. A low feasibility setting loosens these assumptions to account for imperfect recall of who may be exposed, delays in identifying or locating contacts, infrequent or untrained monitoring of symptoms, and imperfect isolation resulting in nosocomial or other infections.