Browsing by Subject "transmission dynamics"

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Early Real-Time Estimation of the Basic Reproduction Number of Emerging Infectious Diseases
(2012-07) Davoudi, Bahman; Miller, Joel C.; Meza, Rafael; Meyers, Lauren Ancel; Earn, David J. D.; Pourbohloul, Babak; Meyers, Lauren Ancel
When an infectious disease strikes a population, the number of newly reported cases is often the only available information during the early stages of the outbreak. An important goal of early outbreak analysis is to obtain a reliable estimate for the basic reproduction number, R-0. Over the past few years, infectious disease epidemic processes have gained attention from the physics community. Much of the work to date, however, has focused on the analysis of an epidemic process in which the disease has already spread widely within a population; conversely, very little attention has been paid, in the physics literature or elsewhere, to formulating the initial phase of an outbreak. Careful analysis of this phase is especially important as it could provide policymakers with insight on how to effectively control an epidemic in its initial stage. We present a novel method, based on the principles of network theory, that enables us to obtain a reliable real-time estimate of the basic reproduction number at an early stage of an outbreak. Our method takes into account the possibility that the infectious period has a wide distribution and that the degree distribution of the underlying contact network is heterogeneous. We validate our analytical framework with numerical simulations.
Simulating School Closure Policies for Cost Effective Pandemic Decision Making
(2012-06) Araz, Ozgur M.; Damien, Paul; Paltiel, David A.; Burke, Sean; van de Geijn, Bryce; Galvani, Alison; Meyers, Lauren A.; Damien, Paul; Burke, Sean; van de Geijn, Bryce; Meyers, Lauren A.
Around the globe, school closures were used sporadically to mitigate the 2009 H1N1 influenza pandemic. However, such closures can detrimentally impact economic and social life. Methods: Here, we couple a decision analytic approach with a mathematical model of influenza transmission to estimate the impact of school closures in terms of epidemiological and cost effectiveness. Our method assumes that the transmissibility and the severity of the disease are uncertain, and evaluates several closure and reopening strategies that cover a range of thresholds in school-aged prevalence (SAP) and closure durations. Results: Assuming a willingness to pay per quality adjusted life-year (QALY) threshold equal to the US per capita GDP ($46,000), we found that the cost effectiveness of these strategies is highly dependent on the severity and on a willingness to pay per QALY. For severe pandemics, the preferred strategy couples the earliest closure trigger (0.5% SAP) with the longest duration closure (24 weeks) considered. For milder pandemics, the preferred strategies also involve the earliest closure trigger, but are shorter duration (12 weeks for low transmission rates and variable length for high transmission rates). Conclusions: These findings highlight the importance of obtaining early estimates of pandemic severity and provide guidance to public health decision-makers for effectively tailoring school closures strategies in response to a newly emergent influenza pandemic.