Everyone is dunking on @toadmeister for being unable to tell 1% from 0.1%. But there's a much bigger problem with any kind of claim that the IFR (infection fatality rate) is X, so we do/don't need to worry. (1/?)

In fact, the IFR is 0.1% or less - if and only if you are under 40. But from there, as we all know, it ramps up massively. These are the latest stats from an Imperial survey

And here it is aggregated in table form (the different columns take account of whether you think antibodies wane or not)

The reason this crisis hasn't affected developing countries as badly, despite their worse health systems, is because they have younger populations. The reason we are in lockdown is not the IFR, but the IFR for the elderly, which is utterly terrifying.

And the reason we can't just cordon off the elderly and go on living our lives is that there are millions of multigenerational households in the UK and similar countries, meaning you can't let the disease run haywire among the young without risking the old (and others)

There are still really good arguments to be had about the merits of lockdowns, the wider economic/social impacts etc. I'm still annoyed for example that the govt won't produce economic modelling on the impact of lockdown two, however often @MelJStride asks.

But to make an IFR-based case, you don't have to show an aggregate figure, you have to show that it's not as fatal to OAPs, because that's why we're doing this...

(Those charts incidentally taken from this report, which finds an IFR for high-income countries of, yes, 1% https://www.imperial.ac.uk/media/imperial-college/medicine/mrc-gida/2020-10-29-COVID19-Report-34.pdf)

Coming back to this because a doctor makes a v good point: the low IFR for the under-40s only applies if you have a functioning healthcare system. If case numbers are high enough that you reach capacity in hospital/ICU, survival rates get hugely worse...