A study from Korea showing why indoor dining is unsafe and why airborne transmission matters. Case B infected case A from 6.5m (~21 feet!) away in *just five minutes*, and case C from 4.8m (15 feet!). Footage shows no interaction—and only those in line of air flow got infected.

So, first note how few such studies we have here. Jealous. This kind of intense shoe-leather epidemiology can give us better answers about potential transmission paths than large=N but less precise tracing which are useful, too but in a different manner. jkms.org/DOIx.php?id=10.3346…

The takeaway is the same. Indoors, we should always wear a mask–there is no way to make indoor restaurants or bars safe, including those outside structures that are essentially indoor. Air flow and talking matter and, indoors, neither six feet nor 15 min are absolute protection.

Folks asking questions! Many of those are answered in the linked study which is exceptionally detailed and well-done. Yes, they had CCTV footage. Yes, they sequenced from the patients to confirm chain. Yes, they actually measured air flow. This is a yeah, it happened, study.

Look, I really want restaurants to survive. I think they should be helped out until the end of the pandemic and those who can afford to do so can do takeout & tip normally to help keep things going for the moment. Where whether permits, distanced outdoor dining is an option imo.

I wrote a post for @insight explaining the details of this amazing restaurant study, comparing it to other similar studies, and discuss what we can learn from all this about both indoor dining and airborne transmission. It’s empowering! zeynep.substack.com/p/small-…