Now that& #39;s three CDC studies—from a Chinese restaurant, a Korean call center, and an American choir practice—all finding that talking, laughing, singing in close quarters, in unventilated interiors, for many hours, is the perfect storm for a COVID super-spreader event.

The Chinese study
https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article

Finding:">https://wwwnc.cdc.gov/eid/artic... Three Guangzhou families sitting in direct path of AC airflow get sick from droplet transmission.

Practical advice: Increase distance between tables in restaurants, increase ventilation, maybe move diners outside.

The Korean study
https://wwwnc.cdc.gov/eid/article/26/8/20-1274-f2

Finding:">https://wwwnc.cdc.gov/eid/artic... Outbreak in Korean call center concentrated on one side of 11th floor "despite interaction btw workers on different floors in the elevators"

Practical advice: risk = exposure X time; shared air more risky than shared surfaces

The Washington study
https://cdc.gov/mmwr/volumes/69/wr/pdfs/mm6919e6-H.pdf?deliveryName=USCDC_921-DM28169

Finding:">https://cdc.gov/mmwr/volu... A long choir practice w/ 61 ppl leads to 32 confirmed cases and 2 deaths

Practical advice: The risk of sustained interaction in close quarters inside is "augmented by the act of singing" (and, one may conclude, shouting)

Putting it all together:

Everything we know from these studies and other global superspreader events (e.g., the Daegu church outbreak in Korea) tells us that huffing and puffing in close quarters with lots of strangers in unventilated inside spaces is a perfect storm.

TLDR: I have no idea how clubs, bars, basketball stadiums, high school gym events, museums get anywhere close to normal without a vaccine—or universal usage of some pretty fantastic mask technology.