  Mitigation strategies that remove infectious individuals from the greater
population have to balance their efficacy with the economic effects associated
with quarantine and have to contend with the limited resources available to the
public health authorities. Prior strategies have relied on testing and contact
tracing to find individuals before they become infectious and in order to limit
their interactions with others until after their infectious period has passed.
Manual contact tracing is a public health intervention where individuals
testing positive are interviewed to identify other members of the community who
they may have come into contact with. These interviews can take a significant
amount of time that has to be tallied in the overall accounting of the outbreak
cost. The concept of contact tracing has been expanded recently into Automated
Exposure Notification whereby cellphones can be used as sensor platforms to log
close contacts and notify the owner in the event that one of their close
contacts tests positive. The intention is that this notification will prompt
the person to be tested and then restrict their interactions with others until
their status is determined. In this paper we describe our efforts to
investigate the effectiveness of contact tracing interventions on controlling
an outbreak. This is accomplished by creating a model of disease spread and
then observing the impact that simulated tracing and testing have on the number
of infected individuals. Model parameters are explored to identify critical
transition points where interventions become effective. We estimate the
benefits as well as costs in order to offer insight to public health officials
as they select courses of action.
