It's not like the CDC has detailed information easily available online about how influenza disease burden is calculated and obtained Oh wait https://www.cdc.gov/flu/weekly/overview.htm …pic.twitter.com/FQ1QmAKUfI
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This raises a conundrum. We want to know how much influenza is around, but (based on research) only about 10-20% of people with infections get a test to see if it's influenza or something else
Thus, we build complex surveillance systems that look at how many influenza cases are REPORTED (based on testing) and infer back to a reasonable estimate of how many actually occurred
Of course, none of this is perfect, because it's tricky stuff, but if you actually read beyond the headlines all of that is explained in minute detail
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