1/ Thanks - effectively all superspreading events are indoors.

Major risk factors appear to be:
- Poor ventilation, crowding, time, perhaps singing (etc.)
- Vulnerable individuals (hospitals, nursing homes, etc.)

@KoenSwinkels

https://www.stopsuperspread.com/p/infographic.html https://twitter.com/Maxwellll12/status/1319484859274776578

2/ My view is that #covid19 policy should encourage people to be outdoors as much as possible.

Less: policing of outdoor behaviour, non-specific contact tracing

More: preventing clusters in hospitals & nursing homes, ventilation upgrades, contact tracing focused on clusters

3/ Focusing on preventing clusters can be more successful than many people think

e.g., different nursing home policies in two different provinces in Canada led to stark differences in outcomes with many deaths prevented

Probably also true for hospitals

https://www.cmaj.ca/content/cmaj/early/2020/09/29/cmaj.201860.full.pdf

4/ There has also been interesting differences in tracing policies in places like Japan - which focused more on identifying clusters / superspreading events

These were lessons from SARS as well as tuberculosis https://asiatimes.com/2020/06/japans-contact-tracing-method-is-old-but-gold/

5/ @JoshOsowicki put me on to this great study of tuberculosis (TB) transmission

The R for active TB cases leading to latent TB was estimated to be 14-45 (huge!)

https://asiatimes.com/2020/06/japans-contact-tracing-method-is-old-but-gold/

6/ Public health learned lessons about TB >100 years ago

Addressing social factors like overcrowding, poor ventilation, poverty made a big difference (perhaps more than treatment or a vaccine -see below)

We probably need more of this old school public health approach right now

7/ There is sometimes too much focus on individual 'superspreaders', when we should focus instead on context (factors that promote super-spreading events)

If a superspreader lives in a forest, do they infect anyone?

cc'ing @prof_goldberg