1/n A cautionary tale of bad #scicomm, in *four* sections, the fourth part being where I learn to take my own advice, the first part where I retro-implement doing so. What are your risks of dying from #COVID19 if you're under 50? Turns out, that's quite tricky.

2/ natural temptation is to look at #CFR — how many died (for each age group) out of all confirmed #COVID19 *cases*, which in many places means out of those ill enough from it to end up in hospital. But that wasn't the question. What the question implies is, what's the * #IFR*?

3/ This is what age-group CFR looks like for #COVID19. But we've already noted that this *doesn't* tell you your chances of dying from it when you're under 50, it only tells you your chances if you get sick enough from it to end up in hospital (roughly).
https://ourworldindata.org/mortality-risk-covid#case-fatality-rate-of-covid-19-by-age

4/ This is what age-group IFR looks like, if you examine as many hard-data studies as you can get your sticky mittens on. This is from a preprint ( https://www.medrxiv.org/content/10.1101/2020.07.23.20160895v4), the best immediate guide I could find, but many big caveats apply! But let's run with this for a moment.

5/ Ignoring all the many (important) caveats that apply, we could say from that:
a/ if you're under 35, you have one chance in 10,000 of dying from #COVID19 if you catch it at all.
b/ 35<you<44: 6 chances in 10,000.
c/ 45<you<54: 2 chances in 1,000 (note the *big* jump in risk).

6/ Over 54? Gets dismal, start w/ 0.7 of a chance out of *100*, go up to 27 chances out of *100* if you're over 85, in other words, #COVID19 is bad news. But that wasn't our question. Our question was, under 35, & under 50.
Under 35? One chance in 10,000 https://twitter.com/Gurdur/status/1303182915501805568

7/ From that meta-study, if you're between 45 & 54, your chances of dying from #COVID19 if you catch it *at all* are 2 chances out of 1,000, say 1 out of 500. But that included those between 51 and 54 inclusive, which mucks it up a little.
That's the first section concluded.