Without a mask, even talking would be enough to transmit the coronavirus

The SARS-CoV-2 coronavirus, or COVID-19 virus, has only been known since December 2019 when it originally emerged in Wuhan, China. As a result, the scientific community is learning more every day about its behavior, its virulence and its dangers, confirming or refuting certain pre-established hypotheses about it. One of them wondered if this coronavirus could be airborne: that is to say, in a way, float and resist in the air for a while before falling back to the ground. According to a new American study, published in the journal Proceedings of the National Academy of Sciences (or PNAS), the COVID-19 coronavirus may resist air suspension longer than expected.

The main mode of transmission of this virus is through liquid droplets. When a person coughs or sneezes, without performing barrier gestures (for example, putting their face on the inside of their elbow), they project tiny drops of water and mucus from their mouth and respiratory tract to several meters in front of her. This is where the rule of distancing at least one meter between each person comes from. The force of these projections propels a good part of the droplets – which, in a sick person, carry a concentration of viral particles – until being confronted by a surface or another person. What we now know is that the rest of the drops can stay suspended in the air for several minutes. Even when someone is just talking. Biologists at the National Institute of Diabetes, Digestive and Kidney Disease in Bethesda, Maryland discovered it in a fairly simple experiment.

Is it an airborne virus?

They observed the number of droplets projected by a sick person addressing, in different amplitudes of voice, the formula “Stay Healthy” inside a closed box. Multiple high-precision lasers passing through it have allowed researchers to quantify the number of droplets emitted but above all to measure the time during which it remained suspended in the air. “This direct observation demonstrated that speaking at a normal rate and amplitude can generate airborne droplets for more than ten minutes, which are eminently capable of transmitting the virus in confined spaces”, conclude the scientists in their study. Indeed, according to them, a strong word is enough to emit thousands of liquid droplets per second. These can resist suspended, without draft or rain, between 8 and 14 minutes. In other words, if the weather is clear outside or if you are in a confined space, a sick person could, in theory, transmit the virus to you without even speaking directly to you. It is enough that she had a conversation with another, a few minutes before, and that you pass by there just after. This simple experience shows how crucial the wearing of a mask is and can prevent this kind of transmission, from unsuspected patients, as a preventive measure.