Washington (AFP)

The new SARS-CoV-2 coronavirus contaminates both surfaces and air near patients, and up to four meters from them, according to a study carried out in a Wuhan field hospital and published by the Centers on Friday American Disease Prevention and Control (CDC).

An important limitation of the study, published by the CDC journal Emerging Infectious Diseases, is that the test used can detect the presence of the virus, but not the amount of viable virus. In other words, it is not because the virus ejected into the air by sneezing or breathing patients can fly up to four meters, that these particles will be in sufficient quantity to infect someone.

Chinese researchers took samples from an intensive care unit (15 patients) at the Huoshenshan field hospital in Wuhan between February 19 and March 2, as well as from a general care unit with less serious patients (24 patients). ).

It is the prefabricated hospital which had been built in 10 days by an army of workers at the start of the epidemic in the city.

Samples were taken from the floors, computer mice, trash cans, bed rails, patient masks, caregiver protective equipment, air vents, as well as from the air in the rooms. several places.

"SARS-CoV-2 was widely distributed in the air and on the surface of objects in the resuscitation and general care departments, which implies a potentially high risk of contamination for nursing staff and other close contacts" , write the researchers.

- Shoe soles -

The most contaminated areas were near intensive care patients. The most contaminated objects were mice, followed by garbage cans and beds and door handles.

But half of the soles of the nursing staff's shoes also had traces of the virus. "We strongly recommend that people disinfect the soles of their shoes before leaving services where Covid-19 patients are found," the researchers conclude.

They also recommend disinfecting the masks after use, before throwing them away.

The virus has also been detected in the air: more often near the patient's bed than near doctors' workstations.

But they found it once four meters from the patient, which makes them write that "the maximum transmission distance of an aerosol of SARS-CoV-2 could be four meters".

The virus was also found on the air vent through which the air in the rooms was exhausted.

Given the significant contamination of the patient environment, the researchers believe that "isolating people with a suspected Covid-19 at home may not be an effective control strategy".

The main mode of spread of the new coronavirus is the relatively large droplets produced when coughing or sneezing.

But we also emit microscopic droplets by speaking and breathing, and the presence of coronavirus in sufficient quantities inside these droplets (aerosols) is the subject of intense scientific debate.

As a precaution, the United States has recommended covering their faces to prevent people who carry the virus but without symptoms from infecting other people by talking or breathing.

© 2020 AFP