The epidemiology of influenza and its control

Abstract

In this chapter we highlight how recent advances in influenza epidemiology can inform existing strategies for disease control. As a field, influenza epidemiology has benefited greatly from analysis of large data sets regarding hospitalization, mortality, and outpatient visits. These data have allowed comparison of the impact of influenza in various climates and the evaluation of the direct and indirect benefits of vaccination, the latter through the vaccination of “transmitter populations” such as school children, to achieve herd immunity. Moreover, the resolution of influenza epidemiology has undergone a leap to the molecular level due to the integration of new antigenic and viral genomic data with classical epidemiological indicators. Finally, the new data have led to an infusion of quantitative studies from the fields of evolutionary and molecular biology, population genetics and mathematics.The progress can be seen in many forms. The emerging field of molecular influenza epidemiology is providing deeper insight into global patterns of viral emergence, the important role of reassortment in generating genetic novelty, and global diffusion of virus variants — including the mysterious but crucial role of the Tropics, especially Southeast Asia, as a source of new variants. Deeper stratification of contemporary and historic epidemiological data is providing a more detailed picture of the effect of age and other host characteristics on outcomes, as well as better estimates of the transmissibility of pandemic and seasonal influenza viruses. Re-examination of observational studies of vaccine effectiveness in seniors is leading to reconsideration of seasonal and pandemic vaccine priorities, while mathematical modelers have developed tools to explore optimal strategies for mitigating a future pandemic. The field of influenza epidemiology has rapidly progressed in the past decade and become truly multidisciplinary. Progress could be sustained in the next decade by even closer ties with virology, evolutionary biology, immunology, and genetics.KeywordsInfluenza VirusInfluenza VaccinationInfluenza PandemicVACC INATIONVersus IRUSThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.