Why CDC Estimates the Burden of Flu Averted by Vaccination

CDC uses a model to estimate the total numbers of influenza (flu) illnesses, medical visits, hospitalizations, and deaths as well as the impact of flu vaccination on these numbers in the United States. Because surveillance systems tracking flu do not capture every flu-related illness, medical visit, hospitalization or death in the United States, CDC feels it is important to estimate and convey the full burden of seasonal flu and the impact of flu vaccination. To do this, CDC uses well-established scientific methods that have been reviewed by scientists outside of CDC to make comprehensive estimates of how flu vaccination affects the total numbers of annual flu illnesses, flu-associated hospitalizations, and flu-associated deaths that occur each year.

By comparing the burden of flu illnesses, hospitalizations, and deaths averted by influenza vaccination each season, CDC can better understand and communicate the benefits of influenza vaccination. Estimates of the burden of flu averted due to vaccination provide clear evidence on the public health impact that vaccination can have in terms of reducing the burden of flu each season.

These estimates underscore the important benefits provided by influenza vaccination, which has been recommended annually in the United States since 2010 for all persons 6 months and older. In addition to quantifying the benefits of influenza vaccination each season, these estimates also highlight areas where improvements in vaccine uptake and vaccine effectiveness could deliver even greater benefits to the public’s health.