New evidence is pointing to the fact that the coronavirus can quickly travel long distances in restaurants, further highlighting how risky indoor dining can be, according to a new study published in the Journal of Korean Medical Science.

The study’s conclusions also raised concerns that the widely accepted standard of six feet when social-distancing may not be enough to keep people safe from contracting the virus.

“In this outbreak, the distances between infector and infected persons were . . .  farther than the generally accepted two meter (6.6-foot) droplet transmission range,” the study’s authors wrote.

“The guidelines on quarantine and epidemiological investigation must be updated to reflect these factors for control and prevention of COVID-19.”

The U.S. Centers for Disease Control and Prevention is currently recommending that diners wear a mask when “less than six feet apart from other people or indoors.”

The agency is also pushing individuals to wear a “mask as much as possible when not eating” and maintain “a social distance of six feet or more in any entryway, hallway or waiting area.” It has even recommended “universal mask use” outside homes.

For the study, the researchers were able to analyze in detail a pair of transmission events that occurred in a restaurant in June. Two customers contracted the virus despite sitting at least fifteen feet away from a third diner, who was eventually found to be positive but asymptomatic.

The research further revealed that the airborne virus had the potential to spread widely in as little as five minutes—much less time than what it takes for an average patron to finish a meal.  

The authors of the study did note that the particular restaurant where the transmissions took place had neither windows nor a ventilation system. Instead, it only utilized ceiling air conditioners that circulated the virus-laden air in the direction of the customers who later tested positive for the virus.  

Droplet “transmission can occur at a distance greater than two (meters) if there is direct air flow from an infected person in an indoor setting,” the study wrote.  

Dr. Scott Gottlieb, the former commissioner of the U.S. Food and Drug Administration, is one high-profile medical expert who recently admitted that he does not dine indoors at restaurants because the coronavirus “risk is too high.”  

He acknowledged that it is certainly possible that some restaurants have minimized the transmission risk of the virus, but it’s still difficult to give an all-clear in any type of indoor-dining environment.  

“People who eat indoors are talking loudly in many cases, and again you’re not wearing a mask,” Gottlieb said in an interview on CNBC.  

“You’re in a confined space. I think there’s no question that’s a higher risk.”  

Ethen Kim Lieser is a Minneapolis-based Science and Tech Editor who has held posts at Google, The Korea Herald, Lincoln Journal Star, AsianWeek, and Arirang TV. Follow or contact him on LinkedIn.  

Image: Reuters