The risk of surface transmission of Covid-19 is low, the US Centers for Disease Control and Prevention said Monday. Far more important is airborne transmission.
“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,” Vincent Hill, Chief of the Waterborne Disease Prevention Branch, said.
Hill said the risk of transmission from touching a surface, while small, is elevated indoors. Outdoors, the sun and other factors can destroy viruses,” Hill said on a CDC-sponsored telephone briefing.
The virus dies “rapidly” on porous surfaces but can persist longer on hard, indoor surfaces.
Research also suggested that surface transmission was more likely in the first 24 hours after a person is infected, and that households where one person had Covid-19 did have a lower transmission rate when the household cleaned and disinfected surfaces.
The CDC has updated its guidance for cleaning and disinfecting surfaces in community settings in light of this transmission risk.
“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.”
Hill said cleaning should be focused on high-contact areas, such as doorknobs and light switches.