Los Angeles Times, SEOUL, South Korea — Dr. Lee Ju-hyung has largely avoided restaurants in recent months, but on the few occasions he’s dined out, he’s developed a strange, if sensible, habit: whipping out a small anemometer to check the airflow.
It’s a precaution he has been taking since a June experiment when he and colleagues re-created the conditions at a restaurant in Jeonju, a city in the southwest of South Korea, where diners contracted COVID-19 from an out-of-town visitor.
Among them was a high school student who was infected with the coronavirus after five minutes of exposure from more than 20 feet away.
The results of the study, for which Lee and other epidemiologists enlisted the help of an engineer who specializes in aerodynamics, were published last week in the Journal of Korean Medical Science. The conclusions raised concerns that the widely accepted standard of 6 feet of social distance may not be far enough to keep people safe.
The study — adding to a growing body of evidence on airborne transmission of the virus — highlighted how South Korea’s meticulous and often invasive contact tracing regime has enabled researchers to closely track how the virus moves through populations.
The study’s authors wrote:
“In this outbreak, the distances between infector and infected persons were … farther than the generally accepted 2 meter [6.6 foot] droplet transmission range.
“The guidelines on quarantine and epidemiological investigation must be updated to reflect these factors for control and prevention of COVID-19.”
KJ Seung, an infectious disease expert and chief of strategy and policy for the nonprofit Partners in Health’s Massachusetts COVID response, said the study was a reminder of the risk of indoor transmission as many nations hunker down for the winter. The official definition of a “close contact” — 15 minutes, within 6 feet — isn’t foolproof.
In his work on Massachusetts’ contact tracing program, he said, business owners and school administrators have fixated on the “close contact” standard, thinking just 14 minutes of exposure, or spending hours in the same room at a distance farther than six feet, is safe … Read more.
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