Lyon (AFP)

Detect Covid-19 by "blowing in the balloon", like a breathalyzer?

At the Palais des Sports in Lyon, a vast experiment is underway, opening up prospects for a return to "real life" after the epidemic.

To Alexandre, 10 years old, Candice Cart, assistant engineer, explains that you have to "take a deep breath".

"And then you will breathe out continuously until there is no more air in your lungs."

The young boy had come to be tested in this large hall in the south of the city because his whole class was closed because of Covid.

“Gently!” He exclaims after blowing the pipe.

"The patients are very intrigued and receptive to this experiment", assures Dr Alexandre Gaymard, virologist at the Hospices Civils de Lyon, in charge of the COVIDAir project.

Over the past month, more than 2,800 Lyonnais have already blown through a pipe in this large machine, the size of a fridge.

It will take twice as much to complete this clinical study.

"The Gerland screening center being quite busy, we should reach our goal by the end of June", hopes Dr Gaymard.

The goal is to be able to identify and quantify the molecules present in an air sample in order to detect people with Covid-19, using a mass spectrometer.

This instrument "will separate and observe the molecules as you exhale. We then obtain a graph which will be interpreted by software", explains the researcher.

The people participating in the experiment all did a PCR test beforehand, so that the two results could be compared in the laboratory.

If the experiment were to be successful, one to two minutes could be enough to be tested for Covid-19.

This technology could therefore be used in places open to the public, during sporting or cultural events, in airports before boarding, or even at the entrance to hospital emergencies to sort patients.

"This machine will be useful in all places where it is necessary to detect quickly", summarizes Dr Gaymard.

- 95% reliable?

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If it is still impossible to draw conclusions from this month of experimentation, preliminary results obtained last year on patients with Covid-19 at the Lyon hospital of Croix-Rousse had demonstrated "a reliability of 95 % in comparison with a PCR test ", according to Alexandre Gaymard.

The COVIDAir study is conducted by a consortium of scientists from the Institute of Infectious Agents of the Civil Hospices of Lyon, the Institute for Research on Catalysis and the Environment (IRCELYON) of the CNRS and the Institute of Analytical Sciences (ISA).

Its conclusions should be released by the end of the year.

Mass spectrometry technology is used in particular during environmental analyzes to detect dangerous particles in the air.

Its recent use in human health could be extended to the detection of other respiratory diseases, the scientists hope.

"We also collect information to detect other viruses, such as influenza or respiratory syncytial virus, responsible for bronchiolitis in infants."

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