Each year CDC estimates the burden of influenza in the U.S. CDC uses modeling to estimate the number of flu illnesses, medical visits, hospitalizations, and deaths related to flu that occurred in a given season.
Some people with influenza will seek medical care, while others will not. CDC estimates the number of people who sought medical care for influenza using data from the 2010 Behavioral Risk Factor Surveillance Survey, which asked people whether they did or did not seek medical care for an influenza-like illness in the prior influenza season.
What methods are used to estimate the number of influenza-associated deaths in the U.S.?
The model uses a ratio of deaths-to-hospitalizations in order to estimate the total influenza-associated deaths from the estimated number of influenza-associated hospitalizations.
I don't know who is the idiot in this scenario, except I know it is not me
the reason is because influenza is not diagnosed, it is estimated
see this page at the CDC
https://www.cdc.gov/flu/about/burden/index.html
How CDC Estimates the Burden of Seasonal Flu in the U.S.