It seems possible that the new coronavirus can be transmitted when people speak and breathe, a senior US government scientist said on Friday as the White House prepares to recommend people to wear masks.

Transmission by air would provide a long-sought explanation for the apparent high contagiousness of the virus responsible for the Covid-19 pandemic, since it appears that infected people without symptoms are responsible for a large part of the contagions, without their knowledge. .

Dr. Anthony Fauci, director of the National Institute of Infectious Diseases and Donald Trump’s epidemic adviser, told Fox News on Friday that “the virus can actually be transmitted when people just talk, rather than just when they sneeze or cough. “

The American Academies of Sciences detailed in a letter sent to the White House on Wednesday several preliminary scientific results tipping the balance in favor of a transmission of the virus via the air exhaled by people (“aerosols” in scientific jargon) , and no longer just by the droplets projected during a sneeze directly on the face of other people or on surfaces (where it has been shown that the virus can survive for hours or even days, depending on the type of surface).

“The research currently available supports the possibility that SARS-CoV-2 can be transmitted by bioaerosols generated directly by the exhalation of patients,” wrote Harvey Fineberg, chair of the committee on emerging infectious diseases, in a letter to names of the Academies and reviewed by several other experts.

He cites four studies and points out that more is needed to better understand the real risk of infection with the new virus. If the virus is actually present in respiration, it is not yet known whether this quantitatively represents an important route of transmission.

In a study, researchers from the University of Nebraska found portions of the genetic code for the virus (RNA) in the air of rooms where patients were isolated. Finding these pieces of virus, however, is not the same as finding the whole virus.

Researchers at the University of Hong Kong recently observed that wearing masks reduced the amount of coronavirus exhaled by patients (the experiment was done with viruses other than SARS-CoV-2).

And Chinese researchers in Wuhan took air samples from various rooms in city hospitals and discovered high concentrations of the new coronavirus, especially in the toilets and rooms where caregivers removed their protective equipment.

In light of these results, American officials are preparing the country for a recommendation to wear masks, no doubt handcrafted, the formulation and level of obligation of which is still unknown.

“I don’t think it will be mandatory,” said Donald Trump on Thursday.

In New York, the mayor has already asked residents to cover their faces outside.

Source : Sciences et avenir