Black Swans
It's been a week of some major WhatsApp aunty gossip. My favourite resource has been Imperial's paper — used by policymakers to forecast what will happen in the case of different government interventions:
Key takeaways from the paper:
1) In their model, social distancing measures last for 5 months (blue shaded area on diagram).
2) An uncontrolled pandemic (do nothing) would lead to 500,000 deaths in the UK.
3) This one's interesting —
Stopping mass gatherings is predicted to have relatively little impact (results not shown) because the contact-time at such events is relatively small compared to the time spent at home, in schools or workplaces and in other community locations such as bars and restaurants.
4) As soon as government interventions are relaxed, infections will begin to rise again — resulting in a peak epidemic later in the year (see orange peak on diagram).
The more successful a strategy is at temporary suppression, the larger the later epidemic is predicted to be in the absence of vaccination, due to lesser build-up of herd immunity.
5) They recognise that measures may need to be in place for many many months and suggest an adaptive approach in the future. Once the outbreak has been controlled (somewhat), they suggest 'business-as-usual' until weekly ICU cases reach a certain capacity (100) — and then the reintroduction of social distancing until weekly ICU cases drop to another threshold (50).
Even with this adaptive approach, these measures will be in place until a vaccine is developed (and distributed) — possibly 12–18 months. Within this timeframe, social distancing would need to be in place for 2/3 of the time.
6) Regional policies on social distancing will be (slightly) more effective and mean that social distancing is in place for less time than a national policy.
Some thoughts (not an epidemiologist, virologist etc.) —
The UK has an incredibly small number of critical care beds — 6.6/100,000 people vs Germany (29.2/100,000), the US (34.7/100,000) and even Italy (12.2/100,000). Increasing capacity could reduce our time in social distancing mode?
Current evidence for hydroxychloroquine/azithromycin is weak — although six clinical trials are recruiting to investigate. To answer some of Trump's other speculation — will the Summer reduce the spread? We don't know.
How to Deal with Black Swans
The Black Swan is a really interesting book on how to think. Some key takeaways which are relevant today—
1) The Narrative Fallacy
People like stories. The most basic form of a story is A did B because of C and then D happened. We like stories so much in fact, that we will morph almost anything we see into one. Some stories I've seen—
China spread coronavirus because they lied about how bad it was and now it's everywhere.
The Government didn't shut pubs/restaurants down quickly enough because they're incompetent and now people are dying.
Everyone's overreacting because they're scared and we're going to have a recession.
Panic buyers have emptied supermarket shelves because they're selfish and now there's no food left.
Stories like this are simple and 1-dimensional. Whilst there might be some truth to them — they don't tell the whole picture. News spreads when it's packaged in an easy-to-follow narrative.
2) Silent Evidence
Diagoras, a nonbeliever in the gods, was shown painted tablets bearing the portraits of some worshippers who prayed, then survived a subsequent shipwreck. The implication was that praying protects you from drowning.
Diagoras asked, “Where are the pictures of those who prayed, then drowned?”
If government interventions work, and we leave this pandemic relatively unscathed — what will people think?
We overreacted. The economy's in the tank because of social distancing. I told you!
That's the problem with silent evidence.
Stay safe and all the best,
Mustafa