This is a hypothesis which further supports the use of masks, mandatory since Monday in France in closed places. Without coughing or sneezing, that is to say just by talking or breathing, we are likely to transmit the coronavirus if there is contamination. This is what suggests, for the first time, a study pre-published this week in the United States, posted on the scientific pre-printing site medrxiv.org. It has yet to be reviewed by a peer-reviewed scientific journal.
A team from the University of Nebraska has for the first time succeeded in replicating SARS-CoV-2 particles taken from the air in rooms of patients with Covid-19. In March, she pre-published another study showing the virus remained in the air of sick hospital rooms. The particles emitted by exhaling air are so light that they remain in suspension for a long time, in the absence of ventilation.
Air taken 30 cm above the feet of the patients
"It's not easy," Joshua Santarpia, professor at the University of Nebraska Medical Center, told AFP about the method of collecting viral particles in the air, using a device the size of a cell phone. "The concentrations are low, there is generally little chance of recovering usable samples."
The researchers sampled the air in the rooms of five bedridden patients, about 30 cm above their feet. The patients were talking, some were coughing. Scientists have managed to collect microdroplets less than five microns in diameter containing virus, and even less than one micron.
They then isolated the virus and placed it in a special medium to make it replicate. They only managed to replicate with certainty only three of the 18 samples, coming from one micron droplets. But Joshua Santarpia is sure: "it replicates in cell culture and is therefore infectious".
The increasingly confirmed airway of transmission
The airborne route of transmission was considered improbable at the start of the pandemic by health authorities in several countries and the World Health Organization, who believe that direct contamination (by spray and droplets directly projected on the face) remains the way main contagion. But the WHO, under pressure from scientists, admitted on July 7 that evidence was emerging on airborne transmission.
"The debate has become more political than scientific, I believe most infectious disease scientists agree that the airway is a component of transmission, although we are still debating its importance," says Joshua Santarpia.
Airborne virus transmission specialist Professor Linsey Marr commented on Twitter that the study presented "strong evidence," adding: "There is infectious virus in the air. It remains to be seen how much to breathe to be infected "
Health
Coronavirus: The current virus is more infectious than before, according to a study to be confirmed
Health
Coronavirus: Immunity could go away in months, study suggests
- Oms
- Contamination
- Science
- Health
- Covid 19