Transport, meeting rooms, locker rooms, gyms … The places where the risk of contamination is higher Covid-19 have several things in common: an enclosed space and a high density of people. Are there places where the risk of contamination is increased?
Closed places with many people
First criterion: « The most risky places are closed places, with little or no ventilation, » said Dr. Kierzek. Among them, restaurants, small shops … « It is an interior virus, » added the specialist.
Second factor: a high density of people. The more people in a small space, less social distancing is observed.
Result: the virus, present in an asymptomatic individual or not, remains in the air. Meeting rooms, sports halls and places of worship are therefore more at risk because they fulfill these two factors, unlike a beach or a park.
Places at risk
* Religious gatherings places: « The churches are particularly affected At the time it is a closed environments but also makes the singing probably increases the production of droplets. » Increasing is the risk of spreading the virus, says Professor Anne. -Claude Crémieux. « This was found in a choir described in the US, » she says. Indeed, it evokes the repetition of 61 choristes1 who participated on March 10 at a rehearsal in Skagit County, northwest of Washington. Among them, 53 people fell ill. At issue: the highly contagious SARS-CoV-2 during an activity such as singing, amid a group of individuals.
* Meeting rooms: they are to flee, especially if physical distancing is not respected. Many people spoke, the room can be small without possibility of opening a window. « Above all, do not remove the masks with which each protects the others » warns Dr. Kierzek. And vigilance must not be relaxed during breaks. « People can protect themselves during work but during breaks, we remove the mask and we no longer pay attention. This phenomenon was highlighted in the hospital » explains Pr. Crémieux.
* Gyms: « People make a physical effort so the breathing quickens and producing droplets intensifies » explains infectious disease. Regarding the risk of being contaminated by touching the surface of a sports machine, Dr. Kierzek’s opinion is clear. « You have to remove the idea that it is a virus that is transmitted by surfaces. It happens, but it is very unlikely, the risk is extremely low. »
* Public transport: the subway, trams and other trains are enclosed areas with potentially many. « In the subway, for example, the mask is mandatory and people who visit their workplaces do not speak, so they do not excrete saliva and there is less risk » reassures Dr. Kierzek adding: » The fact that the doors open, there is a call of air « , promoting the spread of the virus. « Talking increases the risk, but also breathing, shade Pr. Crémieux. It is also face-to-face, proximity without speaking and coughing » she specifies.
Slaughterhouses: clusters were reported in slaughterhouses, including Saint-Brieuc in Brittany, several days after decontainment May 11 « The people who work there have equipment that is not necessarily intended to prevent the circulation of the virus between humans, do not wear the mask properly during breaks or may not have declared their symptoms right away » suggests the professor of infectious diseases. « While in the locker room, removing a place on two is often cramped quarters where we are glued to each other, » says the former employee of a slaughterhouse Olivier Le Bras in France Info2. « Do we have to cross, so there is a contact at one time or another. »
* The changing rooms of a public swimming pool: « What is dangerous is the locker room. These are both hot and humid places with people on the move. We come back to the history of sports halls. As breaths can be accelerated, producing droplets increases « indicates Pr. Crémieux.
* Aircraft « airplane includes a filtering system and ventilation blocks. Air does not circulate throughout the plane but on defined rows. This decreases the number of people affected by the same air block. Thus, the circulation of a virus particle cloud would be very limited and would involve a risk for people rows broken down by the same circuit, « says Dr. Cremieux.
Air conditioning, linked to the spread of the virus?
Air conditioning in a closed circuit without ventilation and in a small room can increase the risk of contamination of the Covid-19. « You have to be careful with the air conditioning, warns Pr. Crémieux, who quotes a cluster born in a restaurant in China. The tables were far apart but the conditioned air that blew made the diners of the two tables infected. »
Indeed Jan. 24, a Chinese family who comes by train from Wuhan déjeune3. Among the guests: a 63-year-old woman, her sister (60) and her niece (34), but also a 62-year-old woman and her 63-year-old husband. Shortly after eating out, the 63-year-old retired woman showed the first signs of the disease and tested positive soon after. 4 of the guests are tested positive in the coming days but also 5 other people also present in the restaurant. Researchers speculate that the source of the outbreak was air conditioning, which could propel droplets over longer distances.
« Air conditioning can turn a viral cloud in the same room. In a large building where the air is diluted, there is not much risk but in a closed car, it is better to avoid » specifies Dr. Kierzek.
Hygiene measures to remember
All closed places are factors that increase the risk of being infected with infected droplets. « But we must not give false security » warns Pr. Crémieux. « Close contact with a person under 2 meters for ten minutes remains a risky situation, inside and outside. In any case, you have to keep your distance and wear the mask is a protection extra… We can’t repeat it. « Hand washing is also essential, as is the daily ventilation of closed rooms.