Estimation of Vaccine Effectiveness


Thursday, January 11, 2018 - 4:00pm


ENGR II 1519


Michael W. Deem - Rice University


I will discuss evolution of the influenza virus, in the context of the 2017/2018 season and historically from 1968 to 2018.  Typically a quasispecies of 
related influenza strains is responsible for the majority of virus in the human population. The virus evolves, however, and this is the reason for the yearly updates to the influenza vaccine.  Part of the selection pressure on the virus to evolve arises from immune history in the population due to prior infection or vaccination, which provide protection against closely related strains. This immune protection is well described by the p_epitope theory of vaccine efficacy for both H3N2 and H1N1 influenza. I will discuss this p_epitope theory.  As a first application, I will use this theory to explain why the adaptations that occur in the egg-based production lower the effectiveness of the vaccine.  In particular, I will show how this theory predicts an effectiveness of 24% for the 2016/2017 vaccine, in comparison to the observed 20%.  As a second application, I will discuss interesting recent examples of the emergence of new flu strains, which were not protected against by the vaccine. I will discuss how the emergence of these new strains  can be detected and predicted, making use of theory of the immune system.


Michael W. Deem works in the area of evolution, immunology, physiology, and materials. He has brought tools from statistical physics to bear on problems in these areas. Of particular focus to him are those biological issues involving randomness, diversity, and correlations. Deem has developed methods to quantify vaccine effectiveness and antigenic distance for influenza, methods to sculpt the immune system to mitigate immunodominance in dengue fever, a physical theory of the competition that allows HIV to escape from the immune system, the first exact solution of a quasispecies theory of evolution that accounts for cross-species genetic exchange, a hierarchical approach to protein molecular evolution, a ‘thermodynamic’ formulation of evolution, a theory for how biological modularity spontaneously arises in an evolving system, and elucidated how static and dynamic measures of human brain connectivity predict complementary aspects of human cognitive performance.

Deem is the recipient of a number of awards, including the NSF CAREER Award, Alfred P. Sloan Fellowship, Camille Dreyfus Teacher-Scholar Award, Allan P. Colburn Award, Professional Progress Award of the AIChE, and Edith and Peter O’Donnell Award of The Academy of Medicine, Engineering & Science of Texas. Deem was a Phi Beta Kappa Visiting Scholar during 2012-2013. He is an editorial board member of the journals “Protein Engineering, Design and Selection,” “Physical Biology,” and “Bioengineering and Translational Medicine.” Deem was a Member of the Board of Governors for the Institute for Complex Adaptive Matter and was a Rice Senator. Deem is a Fellow of the American Institute for Medical and Biological Engineering, the Biomedical Engineering Society, the American Association for the Advancement of Science, and the American Physical Society. Deem is the John W. Cox Professor, Departments of Bioengineering and Physics & Astronomy. Deem is the former Chair of the Bioengineering Department and Founding director of the Systems, Synthetic, and Physical Biology Graduate Program. Deem received his BS from the California Institute of Technology, his PhD from UC Berkeley, and was a postdoctoral fellow at Harvard University.

Event Type: