“As far as I know, in real life scientists like me – an epidemiologist and a doctor – and virologists don’t worry too much about these things,” said David Morens, senior advisor to the director of the National Institute. of allergies and infectious diseases, Anthony S. Fauci.
This is in line with advice from the Centers for Disease Control and Prevention, which updated its “How Covid-19 Spread” webpage to state that “Spread from contacting surfaces is not considered a common way To transmit the virus.
While ongoing research may seem alarming – such as an Australian study published on October 7, which found SARS-CoV-2 can be detected on surfaces such as glass and stainless steel after 28 days – Morens has said the public should not be affected.
Studies like this “basically tend to show that under experimental conditions, which are not real conditions, you can make the virus persist and detect that persistence,” he said. But, he added, that doesn’t mean the virus could infect anyone. “The amount of virus that can persist may not be the amount of virus that can affect you in a real environment.” In the real world, airflow, sunlight, and heat all work quickly to weaken the coronavirus.
Stefan Baral, associate professor in the epidemiology department at the Johns Hopkins Bloomberg School of Public Health, said there was a big difference between a single viral particle that can survive on a particular surface and a virus’s ability to penetrate in a mucous membrane. , cross that mucous membrane and successfully replicate and infect someone. “A single viral particle is extremely unlikely to cause a serious effect,” he said.
But the public’s confusion over the coronavirus and surfaces is understandable, said Angela Rasmussen, a virologist in the Center for Infection and Immunity at the Mailman School of Public Health at Columbia University. “Scientists haven’t really done a very good job of explaining how to get evidence for different types of transmission or different routes of transmission.”
Rasmussen said epidemiologists may have trouble finding concrete evidence that a virus is transmitted through contaminated objects or surfaces, called fomites. In the case of the coronavirus, this is in part because transmission often occurs in the context of large-scale and widespread events, leaving researchers struggling to determine who spoke to whom and who has. touched what surface. “It’s not at all uncommon not to have strong epidemiological evidence of fomite transmission,” she said, “but that doesn’t mean fomite transmission doesn’t happen.
In fact, Rasmussen added, because we know that other respiratory viruses that are transmitted by inhalation, such as influenza and rhinovirus, are also transmitted by fomites, it stands to reason that the coronavirus is probably also transmitted by fomites. “It may not necessarily be the dominant mode of transmission,” she says. And while it may be important for researchers to determine how long the virus remains infectious in various environments, when it comes to everyday life, “I don’t think it’s necessarily wise to wipe the races. . “
Morens agrees. “There’s just a lot of unnecessary worry about these things,” he says. “It’s like standing in the middle of a busy highway with traffic all around you and asking, ‘How lucky is I that I get hit by a meteor? Now, there is a chance, but it’s quite small, and don’t you have other better things to worry about? “
While no environment can be considered completely safe, Morens says we need to view stocks as low, medium or high risk. The time to worry about contaminated surfaces would be when you are in a crowded public place where many people are touching the same surfaces. To illustrate a high-risk area, he cited a public washroom next to a crowded airport lounge, where potentially contaminated people could touch the door handle, light switch, towel dispenser and the tap. This is a situation where you should be super alert; If you wash your hands and then touch the faucet or the doorknob again, for example, you may have infected yourself.
Protection is not gained by washing away everything in the environment, Morens said. “These are the behaviors you adopt to ensure that nothing in the environment, including your own hands, gets into your mouth, nose, or eyes.”
These behaviors include never touching yourself above the neck, wearing a mask (which also reminds you not to touch your face), socially distancing yourself, and making sure your hands are as clean as possible. In that case, you can even walk into a restaurant and touch things there – the chair, the menu – without wiping them down first, and “if the last thing you touch is soap and water or disinfectant for the hands… you’re fine, ”Morens said.
Baral, who has been pushing for the playgrounds to reopen, said one of the factors he takes into account when deciding whether a situation is high risk is the environment the virus might be in. “These viruses don’t survive well outdoors,” he said. said. Coronaviruses like to be surrounded by fluid to protect them, and the fluid evaporates quite quickly on the outside, leaving the virus vulnerable to the elements. He noted that outdoor playgrounds, which were not historically known to be high-risk environments for other viruses, were not identified as areas of common exposure to the coronavirus, months after the start of the pandemic, which he finds “striking”.
However, Baral doesn’t feel the same about indoor environments. There may be environments in people’s homes where the virus is doing well and living on surfaces, he said. For this reason, people should wash their hands immediately as soon as they enter their home from the outside and frequently sanitize common surfaces, such as doorknobs and faucets.
But could all the disinfectants and disinfectants used to clean hands and heavily affected surfaces pave the way for antibiotic-resistant “superbugs”? Not if you’re using soap and water or products recommended by the World Health Organization and CDC, which are alcohol or bleach-based – and not those labeled antibacterial, Rasmussen says. Antibacterial products are the ones that can encourage the development of drug-resistant germs – and they don’t kill viruses, anyway.
Soap and water, alcohol and bleach, on the other hand, work broad spectrum, Rasmussen said, and kill many bacteria as well as viruses. She thinks there really is no need for antibacterial cleaners around the house. “It’s a shame that for a while they were very popular in the consumer market,” she said. “But you can use soap and these other kinds of disinfectants which are more general and will not select resistance.”
Finally, she says, it’s important to remember that “viruses have to have a host and they can’t replicate without a host. So… the primary source of the virus in anyone’s home will be people who live there and not surfaces or the physical environment.
“Even though there is a virus spreading over some things,” she said, “that risk can really be mitigated practically by washing your hands.”