That pretty much makes all statistics on influenza useless non-data doesn’t it?
Not really...CDC can make “in the 95% UI range” estimates...suffice it to say that there are tens of millions of flu/flu caused pneumonia cases per flu season.
https://www.cdc.gov/flu/about/burden/how-cdc-estimates.htm
https://www.cdc.gov/flu/about/burden/index.html