243537 Modeling Global Influenza Risk and Pandemic Severity

Tuesday, November 1, 2011: 3:35 PM

Nita Madhav, MSPH , Research and Modeling, AIR Worldwide, Boston, MA
Vladimir Ivanov, PhD , Research and Modeling, AIR Worldwide, Boston, MA
John Rowe , Research and Modeling, AIR Worldwide, Boston, MA
Introduction: Seasonal and pandemic influenza are major threats to public health. However, as the 2009 H1N1 pandemic has shown, there can be substantial uncertainty in the outcome of a pandemic, especially in the early stages. In addition, seasonal influenza can sometimes cause greater excess mortality than pandemic influenza. Methods: We developed a peer-reviewed, stochastic, metapopulation epidemiologic model to simulate the global spread of influenza. The model includes physical modeling of population movement, age-based contact and disease transmission parameters, and mitigation measures. We also developed a stochastic model to define a suite of realistic influenza scenarios, based on the spatial distribution of animal reservoirs and evolution of influenza viruses. Published data for seasonal and pandemic influenza historical events were used to validate the models, and we conducted sensitivity analyses on key model parameters. Additionally, the effects of pharmaceutical and non-pharmaceutical mitigation measures were investigated. Results: Simulations of historical influenza events, including pandemics of the 20th and 21st centuries, generally showed good agreement with published metrics such as incidence rates and case fatality ratios. The suite of stochastic scenarios ranged in intensity from mild to severe. For the sensitivity analyses, event parameters such as the basic reproduction number (R0), start date, start location, and mitigation measures significantly affected the overall severity of simulated influenza events. Discussion and Conclusion: A metapopulation epidemiologic model can be used effectively to simulate global influenza spread. Such a model can be used to better understand historical influenza events and to plan for future events.

Learning Areas:
Basic medical science applied in public health
Public health biology
Systems thinking models (conceptual and theoretical models), applications related to public health

Learning Objectives:
Describe how a metapopulation epidemiologic model can be used for modeling global influenza spread Explain the importance of age-based contact and transmission parameters for influenza modeling Discuss important contributors to the emergence of an influenza pandemic Identify three event-level factors that can increase influenza severity in a population Compare the efficacy of pharmaceutical vs. non-pharmaceutical interventions based on influenza event severity

Keywords: Infectious Diseases, Epidemiology

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am qualified to present because I am the scientific lead for the pandemic influenza modeling effort at my organization. I have a BS in Ecology and Evolutionary Biology from Yale University, and an MSPH in Epidemiology from Emory University.
Any relevant financial relationships? Yes

Name of Organization Clinical/Research Area Type of relationship
AIR Worldwide Catastrophe Modeling Employment (includes retainer)

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.