Policies for biodefense revisited: The prioritized vaccination process for smallpox

Handling bioterror events that involve contagious agents is a major concern for authorities and a cause for debate among policymakers about the best response policy. At the core of this debate stands the question which of the two post-event policies to adopt: mass vaccination or trace (also called ring or targeted) vaccination. We present a new dynamic epidemic-intervention model that captures key features of the situation and generalizes some previous assumptions regarding the probability distributions of inter-temporal parameters. It is shown that a mixture of mass and trace vaccination policies—the prioritized vaccination policy—is more effective than either of the two aforementioned policies.