The Volokh Conspiracy

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When Will The "Deep Cleanings" Stop?

CDC: "The risk of SARS-CoV-2 infection via the fomite transmission route is ... generally less than 1 in 10,000."


Over the past year, we have learned a lot about COVID-19. Many of the things we thought in the early days proved to be entirely wrong. For a period, the government said healthy people should not wear face masks. Now we should wear two masks! It is entirely unclear where the six-foot rule came from. It is still not clear if the six-foot rule makes any sense. And it is very, very hard to transmit COVID by touching a surface. Remember "fomites"? Last year, I would routinely let my Amazon packages sit outside over night. I even washed plastic bags. There were massive shortages of Lysol wipes. Hand sanitizer could not be found. None of these steps, it now appears, were necessary. The CDC now reports that transmission via touching "fomites" is very, very unlikely.

 Findings of these studies suggest that the risk of SARS-CoV-2 infection via the fomite transmission route is low, and generally less than 1 in 10,000, which means that each contact with a contaminated surface has less than a 1 in 10,000 chance of causing an infection

Last March, almost all workplaces began to perform "deep cleanings." Some (but not all) airlines would sterilize planes between each flight. This process was very expensive, and time-consuming. And may have had little use. The CDC advises that simple disinfectants are enough. And some of the mistings used on planes may actually be not safe:

To substantially inactivate SARS-CoV-2 on surfaces, the surface must be treated with a disinfectant productexternal icon registered with the Environmental Protection Agency's (EPA's) List Nexternal icon or technology that has been shown to be effective against the virus 22. Disinfectant products might also contain cleaning agents, so they are designed to clean by both removing soil and inactivating microbes. Cleaners and disinfectants should be used safely, following the manufacturer guidance. There have been increases in poisonings and injuries from unsafe use of cleaners and disinfectants since the start of the COVID-19 pandemic 23. Some types of disinfection applications, particularly those including fogging or misting, are neither safe nor effective for inactivating the virus unless properly used 24.

Moreover, there is no need for disinfecting general community areas. Soap and water are enough:

Surface disinfection has been shown to be effective for preventing secondary transmission of SARS-CoV-2 between an infected person and other people within households 25. However, there is little scientific support for routine use of disinfectants in community settings, whether indoor or outdoor, to prevent SARS-CoV-2 transmission from fomites. In public spaces and community settings, available epidemiological data and QMRA studies indicate that the risk of SARS-CoV-2 transmission from fomites is low—compared with risks from direct contact, droplet transmission or airborne transmission 8, 9. Routine cleaning performed effectively with soap or detergent, at least once per day, can substantially reduce virus levels on surface. When focused on high-touch surfaces, cleaning with soap or detergent should be enough to further reduce the relatively low transmission risk from fomites in situations when there has not been a suspected or confirmed case of COVID-19 indoors

At some point the deep cleanings will stop.

Update: The New York Times wrote about the end of deep cleanings:

Dr. Allen said that the school and business officials he has spoken with this week expressed relief over the updated guidelines, which will allow them to pull back on some of their intensive cleaning regimens. "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 shift their attention from surfaces to air quality, he said, and invest in improved ventilation and filtration.

"This should be the end of deep cleaning," Dr. Allen said, noting that the misplaced focus on surfaces has had real costs. "It has led to closed playgrounds, it has led to taking nets off basketball courts, it has led to quarantining books in the library. It has led to entire missed school days for deep cleaning. It has led to not being able to share a pencil. So that's all that hygiene theater, and it's a direct result of not properly classifying surface transmission as low risk."