Spread of Covid-19: why restaurants and bars are places at risk

A drink sipped at the counter, a dish of the day swallowed at noon, a pint in hand on the dance floor. These are memories today. How long will it take to live in a world without restaurants, bars and cafes? If the government votes next week on a possible loosening of the trade imprisonment, these living places, a symbol of our cultural identity, could themselves keep the door closed for another week, or even until January 15. less, according to some media, well after the reopening of the shops. “This seems, unfortunately, quite logical, details Benjamin Davido, an infectious disease specialist in Garches (Hauts-de-Seine). It is in places where we don’t wear a mask that we are most contaminated ”.

Several studies have answered the question “where is it most likely to get the virus?” “And” they all say the same thing, “observes the doctor. The most recent, the one from Stanford University, published a few days ago in the journal Nature, analyzed the movements of nearly 100 million Americans, from their mobile data, among their own. place of life and different types of activities during the first wave of the Covid-19 epidemic. Result of the classification, it is in restaurants, sports clubs, cafes, bars and hotels that the risk of contamination was highest. Chicago alone, 85% of infections occurred in 10% of places frequented by the public.

It is difficult to respect physical distances

The same was observed in another American survey, published in September by the Centers for the Prevention and Control of Diseases (CDC). We learn that infected people were 2.5 times more likely than negative cases to have attended a restaurant and nearly four times more likely to have gone to a bar or cafe. “Not only can we not eat and drink with a mask, but in addition, these are closed places and in bars density is important. As alcohol helps, as the evening progresses, respecting physical distances becomes more and more difficult ”, says epidemiologist Pascal Crépey. It is therefore by speaking that we spit and infect our neighbor.

But since the beginning of the epidemic, a question has tormented scientists: how to explain that in certain situations, such as in a restaurant, a person catches the virus without being next to a patient? Did they cross paths when they paid the bill? The answer hardly satisfies the researchers. “We began to have doubts, the only hypothesis of the postillions was not enough”, says Pascal Crépey.

Places where we stay for a long time

Scientists then think of aerosols, these fine virus-containing particles, emitted when a patient speaks and which remain suspended in the air, unlike postillions. And they are right! But one detail still leaves doubts: aerosol-borne diseases are generally much more contagious. One case of measles or whooping cough infects about fifteen people compared to three in Covid-19. Finally, it is a Chinese study, published in September, which will attest to this thesis of aerial transmission. He reports that one traveler, without symptoms, still contaminated a third of his poorly ventilated bus. “Unlike measles, there must be a lot of viral particles in the air to transmit Covid. This explains why most of the clusters described are internal and not external, ”notes Pascal Crépey.