At a glance
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 each flu season.
Overview
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 flu illnesses, flu-related hospitalizations, and flu-related deaths that occur each season.
By comparing the burden of flu illnesses, hospitalizations, and deaths prevented by flu vaccination each season, CDC can better understand and communicate the benefits of flu vaccination. Estimates of the burden of flu prevented due to vaccination provide clear evidence on the public health impact that flu vaccination can have in terms of reducing the burden of flu each season.
These estimates underscore the important benefits provided by flu vaccination, which has been recommended annually in the United States for all people 6 months and older since the 2010-2011 flu season. In addition to quantifying the benefits of flu vaccination each season, these estimates also highlight areas where improvements in flu vaccine uptake and vaccine effectiveness could deliver even greater benefits to the public's health.