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

During each hour of infectiousness, an individual can generate new infections following a negative binomial distribution with dispersion parameter k , with smaller values indicating more variability in infectiousness. Infectiousness while under individual quarantine (before symptom onset) and isolation (after symptom onset) can be reduced by a value between 0, indicating no reduction in the force of infectiousness, or 1, indicating no transmission during that hour. Upon isolation, an individual names a defined proportion of their contacts, who are traced within a defined number of hours and placed under either active monitoring or quarantine. Those under active monitoring are checked with a defined frequency, such as twice daily, and are promptly isolated if found to be symptomatic; however, prior to isolation, there is no reduction in infectiousness. A contact under individual quarantine has infectiousness reduced by a defined factor until onset of symptoms, at which time the contact is isolated.