Indoor Ventilation Proved To Be The Perfect Carrier Of Coronavirus - Study

Indoor ventilation proved to be the perfect carrier of coronavirus - study

Scientists have reconstructed the picture of the spread of infection in a restaurant: visitors who were sitting in the area of one air conditioner were infected. Experts remind that in the premises, standard preventive measures, including keeping distance, may not work.

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In January 2020, a restaurant in Guangzhou, China, experienced an outbreak of COVID-19 among visitors to a five-tiered restaurant. The investigation showed that nine people were infected with the direction of the air flow from the air conditioner. 73 restaurant patrons, whose tables were away from the flow of air, remained healthy.

The ventilation system can make it ineffective to maintain the distance due to the difficult direction of the air flow. Therefore, a distance of one and a half to two meters between tables in a restaurant may not play a preventive role. At the same time, while eating, people cannot be constantly wearing masks.

New article by Chinese scientists has been published online in Emerging Infectious Diseases. Their research illustrates the potential threats of restaurant reopening, The New York Times points out.

What happened

On January 24, a family of five who left Wuhan the day before the city closed down visited a restaurant in Guangzhou. On the diagram, the table of this family is marked with the letter A. On that day, they all felt well, but a day later one of them - a woman of 63 years old - was admitted to the hospital with symptoms of COVID-19.

Layout of tables at the outbreak site. Photo: cdc.gov

Within two weeks, nine more people were COVID-positive who dined in the same room. Five of them were not members of family A, so we can say with a high degree of certainty that they got infected there.

How the people sat

Family A ate in a restaurant with an area of about 140 square meters. Her table was located between the tables of families B and C, whose members fell ill. Air currents from an air conditioner hanging on the wall near the C family spread over the three tables listed, bouncing off the opposite wall and moving in the opposite direction.

In those days, the spread of the coronavirus outside of Wuhan was very low, which allowed doctors to trace all contacts of these families in detail. The remaining 73 people who were in the same room of the restaurant, as well as eight employees of the institution, did not get sick (they were in quarantine for 2 weeks).

The study authors believe that this outbreak of COVID-19 is associated with the spread of the virus in droplets flying from the respiratory tract of an infected woman and dispersed through ventilation. The fact that people who were sitting outside the air conditioner did not become infected gives scientists reason to believe that large droplets played a role in the spread of infection.