A1104
Title: Estimating the effect of contact tracing during the early state of an epidemic
Authors: Junling Ma - University of Victoria (Canada) [presenting]
Abstract: Contact tracing is an important intervention measure to control infectious diseases. A new approach is presented that tracks contacts in a randomly mixed population, which allows the precise modeling of the contact tracing process. The model resulting from this new approach allows for studying the effect of contact tracing and isolation of diagnosed patients on the control reproduction number and number of infected individuals. However, it is found that case counts alone during the early stage of an outbreak before the susceptible population has been depleted are not sufficient to identify key contact tracing parameters such as coverage probability (the fraction of contacts successfully tracked) and testing rate. The reason that a patient is tested for diagnosis is needed, i.e., whether they are quarantined and showing symptoms, voluntarily tested due to symptoms, or contact tracing while showing symptoms. The model is then applied to estimate the effect of contact tracing on the basic reproduction number and epidemic size in Ontario, Canada.
