14 Dec, 6 tweets, 1 min read
Everybody is very optimistic about Omicron.
I HOPE they're right.
I FEAR they're prey to a statistical error, Simpson's Paradox:
Simpson's Paradox says that you can see a trend because you're mixing two populations, but when you separate the populations, the trend is the opposite.
en.wikipedia.org/wiki/Simpson%2…
For Omicron, we might be mixing two populations: immune (through vaccinations or natural immunity) vs. naive (ie they have neither).
Maybe Omicron is *more lethal than Delta* for both groups.

But because those immune have grown dramatically since Delta, mixing both groups appears to lower fatality rates
Eg: 10% of pop immune when Delta arrives & Delta kills 1% of naive and 0.1% of immune --> average fatality rate=0.91%

90% pop immune when Omicron arrives & Omicron kills 1.1% of naive & 0.3% of immune --> average fatality rate=0.38%
It appears that your fatality rate has done down by ~60%, when in truth it's up by ~20%. You just have more immunity.

Let's *hope* this is not the case, but from the data I've seen so far, this sounds like the most reasonable outcome?

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# More from @tomaspueyo

15 Dec
I only see 2 ways out of COVID:
1. An endemic disease that kills a few hundreds of thousands/million of ppl every year
2. A disease eradicated through global vaccination campaigns

I fear there's no 3. A virus that becomes less lethal over time and blends in like a cold
Note that 1 and 3 are pretty similar. In both cases, the disease is endemic and kills a few people every year. The cold doesn't, but the flu does, at ~0.13% of the sick every year.

But what if it wasn't 0.13%? What if it was 0.4%? Would we accept that? It's the ≠ btw 1 and 3
The reason why think we can get to 3 is because that's what probably happened to the 1918 flu: it's H1N1, and after killing so many ppl, it ended up evolving to kill less so it could spread more.
14 Dec
What do we know about Omicron? I fear most ppl are unfortunately too optimistic. They're missing the Key Omicron Question.

Here's a summary of what we know about Omicron, and the key question that remains unanswered:
2 numbers matter in epidemiology: the transmission rate and the fatality rate.

The transmission rate tells you how many people are likely going to catch a virus, and how hard it will be to fight it.

Once you catch it, the fatality rate tells you how bad it will be.
Then there's 2 complications: these numbers interact in weird ways.

1. Ppl believe that viruses that become less lethal spread better.

2. Yet a less lethal virus might end up killing more.

How do we make sense of it all? Let's dive deep
7 Dec
Paradox 1: the more painful feedback is, the more important it is to get it.
7 Dec
Why Europeans colonized America before Africa, in two maps and one story:

Map 1:
Northern Africa, bordering the Mediterranean, has been part of the Eurasian cultures for thousands of years.

South of that, it didn't get conquered until the 19th century, while America got conquered 3 centuries earlier despite being farther. Why?
For centuries, there was the Sahara barrier. The distance to cross was just too big. Impossible by foot, and only possible by sea through the Red Sea in the East, on the path to India, because of inhabitable stops on both sides
9 Nov
Why is Africa the way it is?
Why are its countries where they are?
The relationships between them
The people? The deserts?

Here are X to easily understand Africa better (politics, geography, history, demographics, climate & more)
One of the key ways to look at Africa is through this map: its river basins.

Let's start with the big one in the northeast. It's the Nile's watershed.
Here's northeast Africa at night. See that flower in the middle? That's the Nile through Egypt.
100 million Egyptians live within ~15 miles of its banks. That's ~99% of them.
More details here.

Why?
14 Oct
Parag and I talked for over an hour about migration and the impact it will have in the 21st century. We covered:

- How current nationalism & the image of immigration is short-sighted historically
- The + borders you have, the - borders you have
- The existence of empires today
- African pop growth is overestimated
- The winners of the 21st century will be the most successful states at attracting immigrants
- Which countries would benefit from receiving hundreds of millions of migrants, and why.
- What does the majority think about migration?
- The problem of Gen Z vs. Gen ɑ
- What do Germany and Japan have in common
- The optimal size for a country
- Terraforming Siberia
- How elderly Germans are changing their minds about immigration&seek it instead of fearing it
- How Bulgaria’s immigration approach has is doomed