The infection fatality rate seems to clearly have fallen, but why would it have fallen so much so quickly now that a surge in infections doesn’t kill more people?
and
Explanation 3: Young Getting Infected
My current leading hypothesis is that the difference in IFR between different demographics is substantially greater than previously reported. If under-30 groups see far more asymptomatic cases and very-low-symptom cases than older folks, that would likely cause a substantial underreporting of total cases in those demographics specifically (even more so than in the general population), which would lead to relative overreporting of their IFR—and the reported IFR for those groups is already much lower than for older groups.
This would also partly explain the ongoing confusion about whether there are tons of asymptomatic cases or not. There may be, but only in some demographic groups.
and
My current leading hypothesis is that the difference in IFR between different demographics is substantially greater than previously reported. If under-30 groups see far more asymptomatic cases and very-low-symptom cases than older folks, that would likely cause a substantial underreporting of total cases in those demographics specifically (even more so than in the general population), which would lead to relative overreporting of their IFR—and the reported IFR for those groups is already much lower than for older groups.
This would also partly explain the ongoing confusion about whether there are tons of asymptomatic cases or not. There may be, but only in some demographic groups.