How to improve influenza vaccination rates in the U.S.

Annual epidemics of seasonal influenza occur during autumn and winter in temperate regions and have imposed substantial public health and economic burdens. At the global level, these epidemics cause about 3-5 million severe cases of illness and about 0.25-0.5 million deaths each year. Although annual vaccination is the most effective way to prevent the disease and its severe outcomes, influenza vaccination coverage rates have been at suboptimal levels in many countries. For instance, the coverage rates among the elderly in 20 developed nations in 2008 ranged from 21% to 78% (median 65%). In the U.S., influenza vaccination levels among elderly population appeared to reach a "plateau" of about 70% after the late 1990s, and levels among child populations have remained at less than 50%. In addition, disparities in the coverage rates across subpopulations within a country present another important public health issue. New approaches are needed for countries striving both to improve their overall coverage rates and to eliminate disparities. This review article aims to describe a broad conceptual framework of vaccination, and to illustrate four potential determinants of influenza vaccination based on empirical analyses of U.S. nationally representative populations. These determinants include the ongoing influenza epidemic level, mass media reporting on influenza-related topics, reimbursement rate for providers to administer influenza vaccination, and vaccine supply. It additionally proposes specific policy implications, derived from these empirical analyses, to improve the influenza vaccination coverage rate and associated disparities in the U.S., which could be generalizable to other countries.