Covid-19 in a closed space cannot be caught only by the hands.
It can be transmitted in a spectacular way simply by breathing ... This transmission of Sars-Cov2 by “aerosol” effects, Chinese researchers have just demonstrated once again.
And their study published in the American medical journal Jama looks like a real police investigation.
The case they tell is also reminiscent of the evangelical gathering in Mulhouse in February, one of the main sources of the initial spread of Covid-19 in France or the episode of contagion from customers of a restaurant in Canton at the beginning of last year.
This story takes place on January 19 in Zhejiang province, some 700 km from Wuhan, the Chinese city where it all started.
A woman who has previously been in contact with relatives in Wuhan boards a bus, she goes to a Buddhist event in the city of Ningbo on the east coast.
The round trip lasts almost two hours.
The sexagenarian is a carrier of Covid-19 without knowing it.
Asymptomatic, she does not cough or wear a mask like all the 67 other passengers on the bus.
It takes place between two passengers, right side in a middle row.
Unfortunately for everyone, the coach is poorly ventilated: the air conditioning operates in a closed circuit.
The rest will be catastrophic;
the passenger in turn infects a third of the passengers and among the 23 patients, some were not at all seated in her close circle.
Simple postilions issued by the lady would not have been enough.
Microdroplets, transported by an internal air conditioning without supply of outside fresh air, have done so.
"With the coronavirus crisis, we are rediscovering that pathogens can circulate in the aerial form, explains Gérard Dubois, professor of public health, measles is the typical example, it is an extremely contagious virus by air, but we can also catch a cold or the flu to a lesser extent in this way, ”continues the specialist, who emphasizes that this is precisely what justifies the obligation to“ systematically ”wear a mask in confined spaces.
"If everyone in the same space wears one, the probability of being infected decreases by four, specifies Francis Allard, specialist in air flow and member of the High Council of Public Health (HCSP)" it is really a gesture of caution which is essential, insists the researcher, because certain indications suggest that the Covid-19 would have an airborne infectious power roughly comparable to that of the influenza virus ", continues this expert who notes" that after having been underestimated for six months, this risk ended up being recognized in the spring by the WHO ”(World Health Organization).
Favor continuous ventilation
So to avoid being infected by a carrier neighbor who ignores himself, this teacher-researcher from the University of La Rochelle recommends renewing the air in the workspace: “To reduce the viral concentration effectively, this ventilation must be done continuously and not just occasionally, he warns and if a person in the room is afraid of drafts, then the windows are opened alternately so as to reduce the discomfort ”.
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And if you want to take a break, if only to take off the mask a little, nothing beats a little walk in the open air.
“Outside, the risk of being contaminated by Covid-19 remains very, very low.
There, it is the rules of distance that count, beware of promiscuity ”.
And in addition, it relaxes the legs.