WASHINGTON | The coronavirus causing the COVID-19 was found for months on multiple objects in hotel rooms or hospital, as well as in suspension in the air, but until a study prépubliée this week, he had never been shown that the viral particles in the aerosols were sufficiently intact to replicate and cause an infection.
A team from the university of Nebraska has for the first time managed to replicate the particles of SARS-CoV-2 taken from the air of rooms of sick of COVID-19, dope the hypothesis according to which the virus is transmitted not just by talking to them and the larger droplets emitted by coughing and sneezing, but also by the microscopic droplets that we discharge when we breathe and speak, and which are so light that they remain in suspension for a long time, in the absence of ventilation.
The results are preliminary and have not been reviewed by the editorial board of a scientific journal, who must confirm that the method used by scientists is valid. They were posted Monday on the website medrxiv.org where the scientific community can freely comment on them. But the same team had pre-published in march a study showing that the virus is still present in the air of hospital rooms of the sick, and this article will soon be published by a scientific journal, according to the lead author.
“This is not easy,” told AFP Joshua Santarpia, a professor at the medical centre of the university of Nebraska, about the method to collect virus particles in the air, using a device the size of a mobile phone. “The concentrations are low, one usually has little chance of recovering samples usable “.
The researchers sampled the air in the rooms of five patients in bed, 30 cm above their feet about. The patients were talking, a few were coughing. The scientists were able to collect droplets of less than five microns in diameter that contains the virus, and even less than one micron.
They then isolated the virus and were placed in a special environment to make it replicate. They have managed to replicate with certainty that three of the 18 samples, from droplets of a micron.
But Joshua Santarpia is sure: “it replicates in cell culture and is therefore infectious “.
The airborne route of transmission was considered unlikely at the beginning of the pandemic, the health authorities of several countries and the world health Organization, who estimate that the direct contamination (by spatters and droplets directly projected on the face) remains the main route of contagion. But WHO, under pressure from scientific, was recognized on July 7 as evidence emerged on the transmission by the air.
“The debate has become more political than scientific, I believe that most infectious disease physicians agree that air is a component of the transmission, although we had a debate yet of its importance,” says Joshua Santarpia.
Professor Lindsey Marr, a specialist in aerial transmission of the virus, has commented on Twitter that the study showed ” strong evidence “, adding: “there are the infectious virus in the air. Remains to know how much it is necessary to breathe in order to be infected.”