At the beginning of the coronavirus pandemic, the world health authorities have been saying the virus could be only spread via droplets expelled when contaminated people were coughing or sneezing.
But a study released on September 1 in American medical magazine Jama Internal Medicine shows coronavirus could be also airborne, spreading through the air inhaled and exhaled, reinforcing the recent statements from many respiratory virus experts.
To carry out the study, experts from the Chinese Center for Disease Control have analyzed a very specific situation: a passenger carrying coronavirus, but asymptomatic, who contaminated under one hour a third of a poorly ventilated bus she was on.
These Chinese experts have tested all passengers riding both buses heading to Ningbo on January 19. Among the data taken into account by experts: the duration of the trip (50 minutes), the way back planned with the same buses, lack of facemasks, and the ventilation system making the air recirculate within the passenger compartment without renewing it.
All along the trip, 23 passengers in 68 have been contaminated on the bus the person with coronavirus (but asymptomatic) was. Yet, no infection case has been reported on the other bus.
Experts explain that the contaminated passenger was seated on the right side, in the middle seat of the 3-seat side. But passengers have been contaminated on the front and the back of the bus, that is to say, far outside the droplet expelled contamination area (equivalent to a one to two-meter perimeter).
And the experts of the study concluded that coronavirus has been spread via the air exhaled by the person contaminated (and not droplets by the person since she was no coughing, as she was asymptomatic), and has been spread across the bus because of the ventilation system not renewing the air: “The investigations suggest that, in closed environments with air recirculation, SARS-CoV-2 is a highly transmissible pathogen”, they conclude.