Your awareness on flu testing is an indication of the limits of your knowledge, not a lack of testing. Others in this discussion have provided links with hard d

Your awareness on flu testing is an indication of the limits of your knowledge, not a lack of testing. Others in this discussion have provided links with hard data on testing from the CDC for the US. For a world-wide picture, FluNet w/ GISRS also provide data on testing. These form the basis of overall infection estimates. If you are interested in the methodology of those estimates, here is the CDC overviews, complete with citations for the primary research that informed the creation of their models: https://www.cdc.gov/flu/about/burden/how-cdc-estimates.htm#estimates-Influenza https://www.cdc.gov/flu/about/burden/how-cdc-estimates.htm#e...