The U.S. Centers for Disease Control and Prevention recently said that the risk of COVID-19 being transmitted over surfaces is low, and at times, cleaning surfaces might not be as necessary as previously believed.
Vincent Hill, Chief of the Waterborne Disease Prevention Branch at the CDC, discussed cleaning surfaces during a CDC-sponsored telephone briefing reported by CNN. Hill said, “CDC determined that the risk of surface transmission is low, and secondary to the primary routes of virus transmission through direct contact droplets and aerosols.” Hill added that the risk of virus transmission when indoors is low, but when outdoors it is even lower, saying that the sun and other factors can kill viruses.
“In most situations, cleaning surfaces using soap or detergent, and not disinfecting, is enough to reduce the already low risk of virus transmission through surfaces,” Hill said. “Disinfecting surfaces is typically not necessary, unless a sick person or someone positive for Covid-19 has been in the home within the last 24 hours.”
Earlier this month, the CDC updated its guidelines on disinfecting surfaces, saying, “The principal mode by which people are infected with SARS-CoV-2 (the virus that causes COVID-19) is through exposure to respiratory droplets carrying infectious virus. It is possible for people to be infected through contact with contaminated surfaces or objects (fomites), but the risk is generally considered to be low.”
Hill said that people should focus on cleaning surfaces that have higher contact, like light switches and doorknobs. He also said that lots of disinfecting and cleaning might have a low impact on the transmission of COVID-19 and add to “hygiene theater.”
Hill said, “Putting on a show” to disinfect and clean “may be used to give people a sense of security that they are being protected from the virus, but this may be a false sense of security, if other prevention measures like wearing masks, physical distancing, and hand hygiene are not being consistently performed.”
He added, “It also could make people feel less need to engage in these other important prevention measures.”
The CDC stated that while cleaning surfaces might be helpful to lower the risk of infection transmission within households, “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.”
The CDC said that when data from surface survival and real-world transmission factors are taken into account, “the risk of fomite [or surface] transmission after a person with COVID-19 has been in an indoor space is minor after 3 days (72 hours), regardless of when it was last cleaned.”
As more and more people attempted to disinfect surfaces in order to protect themselves from the coronavirus over the past year, the CDC found that this practice can also be dangerous.
“Public inquiries indicate that some people may purposely drink, inhale, or spray their skin with disinfectants, without understanding that use of disinfectants in this way can cause serious harm to their bodies,” Hill said.
According to the CDC, “There have been increases in poisonings and injuries from unsafe use of cleaners and disinfectants since the start of the COVID-19 pandemic. Some types of disinfection applications, particularly those including fogging or misting, are neither safe nor effective for inactivating the virus unless properly used.”
Routine cleaning is helpful in order to “reduce virus levels on surfaces,” according to the agency. The CDC, however, stresses that while infection can happen through contact with surfaces, the main way that COVID-19 spreads is through “exposure to respiratory droplets carrying infectious virus.” It also suggests that people disinfect indoor community areas if there is a known or suspected case of COVID-19.