what contamination on the surfaces?

How can you be infected with the coronavirus? Within the scientific community, the question is far from settled. It is known that the virus is transmitted by direct contact, by droplets from coughing, sneezing or simply speaking.

Hence the need for physical distancing of at least one meter between people, and the fact of sneezing and coughing into his elbow. Likewise, we know that contaminated droplets may remain attached to certain surfaces. If you touch them, you can catch the virus. It is for this reason that regular hand washing is recommended.

But in the same way as the question of contamination in the air is not yet resolved, it is not really known how high the risk of being contaminated by touching certain surfaces.

72 hours on plastic, 4 hours on copper …

The Ministry of Health explains that “under conditions favorable to its survival, the virus could survive, in the form of traces, several days on a surface”. The virus can in fact attach itself to the hands, handkerchiefs or another affected object (doorknob, elevator button, etc.). Several studies have shown that Covid-19 can persist for a long time on these inert surfaces. On plastic and stainless steel, it would last 72 hours. That’s less than 24 hours on cardboard and less than four hours on copper. It all depends on the temperature and whether the humidity conditions are favorable.

Just after the passage of a contaminated person, you can be contaminated if you touch the surface, and then bring your hand to your face. We also know that other types of coronavirus can be transmitted through inanimate objects.

But after a few hours, the virus breaks down. It is not because it is still found in trace amounts that it is sufficient to infect someone. The whole difficulty of scientists’ work consists in knowing how long the virus really remains contagious, depending on the surface, but also on all the temperature and humidity conditions that can be encountered.

“Exaggerated” studies?

On this subject, the World Health Organization remains cautious. She explains that there is “hard evidence” of the possibility of surface contamination, but that there is “no specific report which directly demonstrates fomite transmission”, ie, through an inanimate object. “People who come into contact with potentially infectious surfaces also often have contact with a contagious person., which makes the distinction between respiratory droplet transmission and inanimate object difficult to discern, “says the WHO.

This is what makes the French government say that “the great transmissibility of COVID-19 is not linked to its survival on surfaces, but to its transmission when we cough, sneeze, discuss or by the droplets expelled and transmitted by the hands “.

For some scientists, the contagion through surfaces is exaggerated. On July 3, Professor Emanuel Goldman of New Jersey Medical School in the United States published in the scientific journal The Lancet an article in which he defends this theory. “The longest survival (6 days) of SARS-COV on surfaces was found by placing a very large initial virus sample […] None of these studies present scenarios resembling real-life situations, “he writes. The surfaces are actually much less contaminated than what scientists are testing,” he says. the precautionary principle makes them too alarming.

How to avoid contamination?

Anyway, it is better to avoid taking risks, especially when you are or when you are around fragile people. So what can be done to avoid surface contagion? One of the first things you can think of is to wear gloves. The hands thus protected, one can imagine that the problem disappears. Except no, the WHO tells us. Gloves give a false sense of security, which can be dangerous. “Regular hand washing protects against COVID-19 better than wearing rubber gloves. The virus can be found on the gloves and there is a risk of contamination if you touch your face with the gloves on.” , explains the WHO.

If you choose to wear them anyway, remember not to touch the gloves when you take them off, wash your hands well, and disinfect items you touched with the gloves, such as your cell phone.

The only solution promoted by the World Health Organization is to clean surfaces that could be contaminated. “The surfaces can be easily cleaned with a common household disinfectant which will kill the coronavirus”, WHO writes. However, pay attention to the type of product you use on your fragile surfaces, like on your phone. Likewise, if you buy items in a store, and especially clothes, it is advisable to wash them at a high temperature and insulate them for a few days in a separate bag. Finally, and we can never say it enough, you should avoid touching your face as much as possible and wash your hands regularly, whether with a hydroalcoholic solution or with soap and water.

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