“CDC has determined that the risk of surface transmission is low, and secondary to the primary pathways of virus transmission via direct contact droplets and aerosols,” said Vincent Hill, chief of the Waterborne Disease Prevention Branch, during a CDC-sponsored telephone briefing. .
Hill said the risk of transmission from touching a surface, while small, is increased indoors. Outdoors, the sun and other factors can destroy viruses, Hill said.
The virus dies “quickly” on porous surfaces, but can last longer on hard surfaces indoors.
Research also suggested that surface transmission was more likely in the first 24 hours after a person was infected, and that households where one person had Covid-19 had slower transmission rates when the household cleaned and disinfected surfaces.
“In most situations, cleaning surfaces with soap or detergent, rather than disinfecting, is enough to reduce the already low risk of virus transmission across surfaces,” said Hill. “Surface disinfection is usually not necessary unless a sick person or someone positive for Covid-19 has been in the house within the past 24 hours.”
Hill said cleaning should focus on high-contact areas, such as doorknobs and light switches.
Household cleaning products are a hazard
People may use household cleaning products to protect themselves from Covid-19, but misuse can have dangerous consequences, Hill added.
Regular cleaning and disinfection of surfaces can have minimal impact on viral transmission and contribute to “ hygiene theater, ” he added.
‘Putting on a show’ to clean and disinfect ‘can be used to give people a sense of security that they are being protected from the virus, but this can be a false sense of security, if other prevention measures, such as wearing masks, physical distance, and hand hygiene are not performed consistently, ”said Hill.
“It can also reduce people’s need for these other important prevention measures.”
Additional data shows that the disinfectants themselves can pose a risk.
“Public investigations show that some people intentionally drink, inhale, or spray disinfectants on their skin, without realizing that using disinfectants in this way can seriously harm their bodies,” he said.
Hill cited June 2020 CDC research that found that of those surveyed, “only 58% knew that bleach should not be mixed with ammonia because mixing bleach and ammonia creates a toxic gas that damages people’s lungs.”
And bleach itself can be harmful.
“Nineteen percent wash food products with bleach, which can lead to consumption of bleach that is not washed off, which can damage the body because bleach is toxic. Eighteen percent used household cleaners on bare skin, which can damage the skin and cause rashes and burns. , ”said Hill.
Hill added that surveillance data shows that calls to poison centers for sanitizers in 2020 were higher than in 2018 or 2019.
Alternative disinfection methods can also be a waste of time or even risky, the CDC says in the updated guidelines.
“The effectiveness of alternative methods of surface disinfection, such as ultrasound, high-intensity UV radiation, and blue LED light against the virus that causes COVID-19, has not been fully established,” the CDC says on its updated website.