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A newly published research letter suggests that three healthy families in China may have contracted the coronavirus virus after it traveled via air conditioning at a restaurant that also served infected people.
The early-release research letter, which will be published in the Emerging Infectious Diseases journal in July, notes that 10 people from 3 different families were affected during the period of Jan. 26-Feb. 10, 2020, at a restaurant in Guangzhou, China.
"We conclude that in this outbreak, droplet transmission was prompted by air-conditioned ventilation," the researchers wrote. "The key factor for infection was the direction of the airflow. Of note, patient B3 was afebrile and 1 [percent] of the patients in this outbreak were asymptomatic, providing a potential source of outbreaks among the public."
The scientists noted that "aerosolized droplets can remain in the air and travel long distances" of more than one meter, but acknowledged that in this instance, the transmission of the virus can't be explained by droplet transmission.
"Larger respiratory droplets (>5 μm) remain in the air for only a short time and travel only short distances, generally <1 [meter] (2,3)," the researchers added. "The distances between patient A1 and persons at other tables, especially those at table C, were all >1 [meter]. However, strong airflow from the air conditioner could have propagated droplets from table C to table A, then to table B, and then back to table C."
A recent study from the Centers for Disease Control and Prevention suggested the coronavirus can travel as far as 13 feet in the air.
Despite the obvious implications for restaurants, many of which are struggling during the pandemic, the researchers found that the other 73 patrons were not affected. They were quarantined for 14 days and did not show symptoms.
As a result, the researchers recommended that social distancing practices that have been put in place remain when restaurants begin to open their dining rooms.
"To prevent spread of COVID-19 in restaurants, we recommend strengthening temperature-monitoring surveillance, increasing the distance between tables, and improving ventilation," they wrote.
Currently, there is no known scientific cure for the disease known as COVID-19. However, there are several trials, including repurposed drugs such as hydroxychloroquine and plasma from recovered COVID-19 patients, currently underway.
As of Wednesday morning, more than 2.58 million coronavirus cases have been diagnosed worldwide, more than 825,000 of which are in the U.S., the most impacted country on the planet.