TORONTO — A new study has found that the novel coronavirus can survive on some forms of fabric and transmit to other surfaces for up to 72 hours in a laboratory setting.
The study, conducted by researchers at the De Montfort University (DMU) in Leicester, U.K., reported that traces of the coronavirus can remain infectious on polyester, polycotton, and 100 per cent cotton for up to three days.
“When the pandemic first started, there was very little understanding of how long coronavirus could survive on textiles,” lead researchers and DMU microbiologist Dr. Katie Laird said in a press release.
“Our findings show that three of the most commonly used textiles in healthcare pose a risk for transmission of the virus. If nurses and health-care workers take their uniforms home, they could be leaving traces of the virus on other surfaces,” she added.
To find this out, researchers added droplets of a model coronavirus called HCoV-OC43, which they reported has a “very similar structure and survival pattern” to SARS-CoV-2, the virus that causes COVID-19, to the three types of fabric.
The researchers then monitored the virus on each material for 72 hours in a lab-controlled setting.
The study, which is currently under peer-review, reported that polyester posed the highest risk for transmission of the virus, with infectious particles still present on the fabric after three days.
With 100 per cent cotton fabric, researchers reported that the virus lasted for 24 hours while it only survive for six hours on polycotton.
Researchers also evaluated the “most reliable wash method” for removing the virus on these materials.
Using 100 per cent cotton, the researchers conducted multiple tests using different water temperatures and wash methods, including domestic washing machines, industrial washing machines, hospital washing machines, and an ozone or highly reactive gas wash system.
The study found that the “agitation and dilution effect of the water” in all of theses washing machines was enough to remove the virus.
However, researchers noted that when the textiles were soiled with an artificial saliva containing the virus, mimicking the risk of spread from an infected person’s mouth, they reported that traces of the virus survived after going through a domestic washing machine.
In this case, the study said it was only when researchers added a detergent and increased the water temperature that the virus was “completely eliminated.”
According to the study, the virus was stable in water up to 60 C, but became inactivated at 67 C.
The researchers also evaluated whether the fabrics posed a cross-contamination risk during washing.
The team evaluated this by placing clean clothes in the same wash as uniforms contaminated with the virus. They found that “all wash systems” removed the virus and there was “no risk of the other items being contaminated.”
Despite this, Laird said the contaminated clothes still pose a threat to health-care workers prior to being washed by transferring to other surfaces if they are brought home.
“While we can see from the research that washing these materials at a high temperature, even in a domestic washing machine, does remove the virus, it does not eliminate the risk of the contaminated clothing leaving traces of coronavirus on other surfaces in the home or car before they are washed,” Laird said in the release.
In response, she has recommended to the U.K. government that health-care staff not take their uniforms home and instead have them laundered in hospitals or by an industrial laundry.
“These wash methods are regulated and nurses and health-care workers do not have to worry about potentially taking the virus home,” Laird said.