When the coronavirus began to spread in the United States last spring, many experts warned of the danger to surfaces. Researchers report that the virus can survive for days on plastic or stainless steel. are infected.
The Americans responded kindly by wiping the food, quarantining the mail, and clearing the shelves of pharmacies of chlorox wipes. Facebook closed its two offices for “deep cleansing”. The New York Metropolitan Transportation Agency began disinfecting subway cars every night.
But the era of “hygiene theater” may have come to an unofficial end this week when the CDC updated its surface cleaning guidelines, noting that the risk of contracting the virus by touching a contaminated surface was less than 1 in 10,000.
“People can be infected with a virus that is caused by contact with COVID-19 contaminated surfaces,” said Dr. Rochelle Valensky, director of the CDC, at a White House briefing on Monday. “However, evidence has shown that the risk of transmission through this route is actually low.”
Scientists say that the reception is long overdue.
“Finally,” said Lincy Marr, a Virginia Tech airborne virus expert. “We’ve known this for a long time, but people are still very focused on cleaning the surface.” He added. “There is really no evidence that anyone ever got COVID-19 by touching a contaminated surface.”
In the early days of the epidemic, many experts believed that the virus spread mainly through large respiratory droplets. These droplets are too heavy to travel long distances in the air, but can fall on objects: surfaces.
In this context, it seems to make sense to focus on cleaning each surface. “Surface cleaning is more familiar,” Mar said. “We know how to do it. You can see how people do it, you see the clean surface. And so I think it makes people feel safer. ”
But over the past year, it has become increasingly clear that the virus is spreading mainly through airborne droplets, which can last longer. և Door handles and subway seats are not enough to keep people safe.
“The scientific basis for all this concern about surfaces is too thin, too thin for anyone,” said Rutgers University microbiologist Emanuel Goldman, who wrote last summer that the risk of surface transfer was too high. “This is a virus that you get through breathing. “It’s not a virus you touch.
The CDC has previously acknowledged that surfaces are not the primary means of spreading the virus. But the agency’s announcements went even further this week.
“The most important part of this update is that they are clearly conveying to the public the correct, low-risk surface area, which is not a clear message from the last year,” said Ozef Allen, a safety expert at Harvard TH Chan School of Public Health.
It is theoretically possible to catch the virus from the surface, he said. But it requires a lot to be wrong. Very fresh, infectious virus particles must be placed on the surface and then a relatively large amount of them quickly transmitted to someone’s hand and then to the face. “Being on the surface is not equal to risk,” Allen said.
In many cases, cleaning with plain soap և water, in addition to hand washing և wearing a mask, is sufficient to reduce the likelihood of surface transfer, according to the CDC Updated Cleaning Guide. The agency notes that in most everyday scenarios and environments, people do not need to use chemical disinfectants.
“I think what works very well tells us what we don’t need to do,” said Donald Milton, an aerosol scientist at the University of Maryland. “Blurring too much chemical spray is not helpful.”
Still, the guidelines suggest that if someone with COVID-19 has been in a certain area during the last day, the area should be “cleaned” and disinfected.
“Disinfection is recommended only indoors, in schools or homes where COVID-19 has been suspected or confirmed in the last 24 hours,” Valensky told a White House briefing. “In addition, in many cases, fog, smoke, large area or electrostatic precipitation is not recommended as the main method of disinfection. Several safety risks must be considered.”
And the new cleaning guidelines do not apply to health care facilities, which may require more intensive cleaning and disinfection.
Saskia Popescu, an infectious disease epidemiologist at Kason Mason University, said she was pleased to see the new guideline, which “reflects our growing data on transmission throughout the epidemic.”
However, he noted that some regular cleaning and good hand washing practices can be continued to reduce the risk of infection, not only of the coronavirus, but also of any other pathogen that may be present on a particular surface.
Allen said those in charge of the school’s business, with whom he spoke this week, had expressed concern about the updated guidelines, which would allow them to withdraw from their intensive cleaning routines. “This frees up a lot of organizations to spend that money better,” he said.
Schools, businesses and other institutions that want to keep people safe should focus on air quality, he said, և invest in improved ventilation և filtration.
“This is going to be the end of deep cleaning,” Allen said, noting that undue attention to surfaces had a real cost. “It has led to closed playgrounds, the removal of nets from basketball courts, the quarantine of books in the library. This led to deep cleaning all day missed at school. This made it impossible to share a pencil. So this is hygiene theater, it’s a direct result of not properly classifying surface transfer as low risk. ”