A case fatality rate (CFR) is calculated based on confirmed cases. The CFR for the flu[1] or any other disease is roughly based on the number of people who pres

A case fatality rate (CFR) is calculated based on confirmed cases. The CFR for the flu[1] or any other disease is roughly based on the number of people who present to the hospital and are diagnosed, with or without serological testing. Therefore, in places with drive-by testing the CFR will be artificially lower. Likewise, using total infected as the denominator makes it a totally useless figure for comparison. Knowing that, it seems pretty clear that COVID-19 is more-or-less 10x deadlier[2] than seasonal influenza, as the CFR for seasonal flu is ~0.1-0.2%. [1] It's a little more complicated with the flu because of underreporting. I guess elderly pneumonia is common enough that doctors don't always care why it developed. So apparently the CDC uses a more complex model (e.g. total number of pneumonia cases minus base rate, non-flu season cases). But what they're trying to estimate is the CFR, which is by definition deaths/confirmed. [2] At least from an epidemiological perspective, regardless of the percentage of symptomatic cases / infections. At the end of the day what matters is how many will die, not how scared someone should be if they're infected.