Every day, Le Parisien is mobilized to answer your questions around the coronavirus. Today we are interested in the questioning of Jacques, who asks us if the virus can remain present on a doorknob.
According to several studies, the SARS-CoV-2 coronavirus has a “survival” time on surfaces that can go up to several days. According to initial work published on February 6 in the Journal of Hospital Infection, this virus could remain present for up to five days on steel and metal, at a temperature of 20 degrees, and between two and six days on plastic.
Other researchers, whose results appeared in the New England Journal of Medicine on March 17, found traces of the virus on plastic and steel 72 hours after spraying. On copper, on the other hand, the traces had disappeared after four hours.
Open the doors with the elbow
But beware: just because there are traces of viruses on a surface, for example a plastic or metal door handle, does not mean that you will be contaminated by touching it. “The amount of infectious virus at a given time depends on the initial amount and on a mathematical constant called the half-life. This varies - on solid surfaces - depending on the nature of the support, the temperature, the degree of hygrometry, the exposure to certain radiations ... ", underlines Vincent Maréchal, professor of virology at the Sorbonne, questioned by the Parisian.
"It is not because the virus persists that it is enough to infect a person who touches this surface," says the government on its site, recalling that the coronavirus is transmitted mainly by secretions from the mouth and nose.
Furthermore, both viruses also showed a 3-log decrease in infectious virus on stainless steel and plastic surfaces after 48-72 hours. This suggests that, while viruses can stay on some surfaces for days, their infectious titer is greatly reduced (1000-fold).
- Dr. Angela Rasmussen (@angie_rasmussen) March 11, 2020On an outside surface, the virus could quickly lose its viral load according to several experts, even if it is still unknown to this coronavirus. The government considers that "it may be useful, as a precaution, to clean frequently and recently affected surfaces".
Manufacturers have also invented devices to open a door without having to put your palm in it. In Toulouse, the resuscitation service at the Pasteur clinic in Toulouse will, for example, be equipped with elbow handles designed by an engineering school, Icam.
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You can ask us all your questions about coronavirus by filling out our form or directly at coronavirus@leparisien.fr. Find all the answers previously published on our dedicated page.