Professor Margaret Brandeau from Stanford University will present a special seminar for the Department of Statistical Sciences, entitled, "Structural Sensitivity in HIV Modeling: A Case Study of Vaccination".

Many potential HIV prevention and treatment policies are evaluated using epidemic models, instantiated using the best available data. However, structural assumptions in such models, such as the choice of network or compartmental model type or the inclusion of different types of heterogeneity across individuals, might affect model predictions as much as or more than the choice of input parameters. We explore the potential implications of structural assumptions on HIV model predictions and policy conclusions. We perform a case study of the effects of a hypothetical HIV vaccine in multiple population subgroups over eight related transmission models, which we sequentially modify to vary over two dimensions: parameter complexity (e.g., the inclusion of age and HCV comorbidity) and contact/simulation complexity (e.g., aggregated compartmental vs. individual/disaggregated compartmental vs. network models). We find that estimates of HIV incidence reductions from network models and individual compartmental models vary, but those differences are overwhelmed by the differences in HIV incidence between such models and the aggregated compartmental models (which aggregate groups of individuals into compartments). For aggregated compartmental models, the differences introduced by parameter complexity also translate into substantial differences in cost-effectiveness estimates. Parameter complexity does not appear to play a consistent role in differentiating the projections of network models.

Professor Margaret Brandeau is the Coleman F. Fung Professor in the School of Engineering and a Professor of Medicine (by Courtesy) at Stanford University. Her research focuses on the development of applied mathematical and economic models to support health policy decisions. Her recent work has focused on HIV prevention and treatment programs, programs to control the spread of hepatitis B virus, and public health preparedness plans. 

She is a Fellow of the Institute for Operations Research and Management Science (INFORMS) and a member of the Omega Rho International Honor Society for Operations Research and Management Science. From INFORMS she has received the President’s Award (recognizing important contributions to the welfare of society), the Pierskalla Prize (for research excellence in health care management science), the Philip McCord Morse Lectureship Award, and the Award for the Advancement of Women in Operations Research and the Management Sciences. She has also received the Award for Excellence in Application of Pharmacoeconomics and Health Outcomes Research from the International Society for Pharmacoeconomics and Outcomes Research, and a Presidential Young Investigator Award from the National Science Foundation, among other awards. Professor Brandeau earned a BS in Mathematics and an MS in Operations Research from MIT, and a PhD in Engineering-Economic Systems from Stanford.