Thread by @GidMK

The CDC estimates that the SYMPTOMATIC CASE-FATALITY RATE (CFR) for influenza is ~0.1%

The estimate of the INFECTION-FATALITY RATE (IFR) is closer to ~0.05%, due to asymptomatic flu cases

It's VERY HARD to compare the CFR of influenza to the CFR of COVID-19, because the DENOMINATORS (number of people tested) are very different

But we CAN compare the IFRs

The POPULATION IFR of COVID-19 is (very crudely) 0.5-1%, although this varies enormously with the age breakdown of people infected by the disease

So, about 10-20x higher than seasonal influenza

But EVEN THIS isn't an apples-to-apples comparison. The IFR of COVID-19 is calculated by dividing CONFIRMED DEATHS by ESTIMATED INFECTIONS

The IFR of influenza is calcualted by dividing MODELED DEATHS by MODELED INFECTIONS

Because we don't routinely test for influenza in every person who gets symptoms in a normal year, we use hospital coding and excess fatalities to ESTIMATE the total number of infections and deaths

This pushes the IFR UP

But EVEN USING THIS HIGHER FIGURE FOR INFLUENZA we see that the IFR of flu is 10-20x lower than COVID-19

fin.