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This study provides novel evidence that human coronaviruses can persist on textiles for up to three days and are readily transferred from polyester textile to other surfaces after
72 hours of incubation . is COVID-infected – and perform hand hygiene after removing their personal protective equipment ( PPE ).
Other research is helping fill in knowledge gaps around SARS-CoV-2 and laundering processes .
Paton , et al . ( 2021 ) investigated the viability over time of SARS-CoV-2 dried onto a range of materials and compared viability of the virus to RNA copies recovered , and whether virus viability is concentration dependent . The researchers found that viable virus persisted for the longest time on surgical mask material with a 99.9 percent reduction in viability by 124 hours . Viability of SARS-CoV-2 reduced the fastest on a polyester shirt , with a 99.9 percent reduction within 2.5 hours . Viability on cotton was reduced second fastest , with 99.9 percent reduction in 72 hours . RNA on all the surfaces exhibited a one log reduction in genome copy recovery over 21 days .
Paton , et al . ( 2021 ) emphasize that designating materials as porous and non-porous may be an oversimplification of the surfaces studied : “ The surface of a surgical mask is porous but is made up of overlapping hydrophobic fibers ; similarly , Tyvek material is produced with non-woven fibers of high density hydrophobic polyethylene but presents microscopic pores on the surface . In the context of our study , relatively low amounts of liquid are being added to these surfaces . Thus , these small droplets of liquid cannot penetrate into the materials , as their hydrophobicity ensures the droplets of liquids remain on the surface of the material during the drying process ; making the surfaces behave more like a non-porous one . Our results show that the porous but hydrophobic surfaces of the surgical mask , disposable gown and Tyvek coverall produce similar decay rates when compared to the non-porous hydrophobic surfaces of stainless steel with a five log10 reduction in recovered infectivity over seven days . Viable SARS-CoV-2 was recovered from these surface materials over longer periods of time compared to the truly porous and hydrophilic surfaces tested , cotton and woven polyester .”
As the researchers observe , “ Following a 4.73 log10 decrease , infectious virus was recovered from cotton material up to three days after inoculation ; matching previous studies , reporting more rapid inactivation of virus particles on cotton surfaces compared to others . These results may be attributed to two factors unrelated to any potential anti-viral activity of the material : retention of virus within the cotton fiber matrix , or losses during the inoculum application due to wicking . Due to the cotton ’ s hydrophilic , woven nature , the liquid inoculum rapidly absorbs and penetrates into the fibers which , when dried , might cause interactive forces , limiting the release of virus particles , which is shown by a greater than 1 log10 reduction in recovery of viable virus after the drying period . This decrease in detection of viable virus may therefore be attributable to inefficient recovery from this specific type of material rather than increased inactivation . This result indicates that viral particles may remain in cotton fibers after contamination posing a forward transmission risk , but they will likely not be released from the substrate to cause infection . Though polyester , produced from polyethylene terephthalate , is hydrophobic , when spun into fine fibers , aligned in the same orientation and woven into fabric , it behaved like the other woven fabric tested , cotton . It is possible that the aligned polyester fibers which are close together , but not fused , causes capillary action to draw the liquid into the interstitial spaces between the fibers and trap the virus particles . Virus that was inoculated onto polyester sports shirt was rapidly inactivated to unrecoverable levels in one day ; there may also be interaction between the chemicals used to process / color the fabric and the virus .”
Owen and Shivkumar , et al . ( 2021 ) investigated the environmental stability of human coronaviruses HCoV-OC43 and HCoV-229E on different textile fiber types and the persistence of HCoV-OC43 on textiles during domestic and industrial laundering . This study demonstrated that human coronaviruses ( 5 log10 50 percent tissue culture infective doses [ TCID50 ]) remain infectious on polyester for more than 72 hours , cotton for more than 24 hours , and polycotton for more than six hours . The researchers found that HCoV-OC43 was also able to transfer from polyester to PVC or polyester after 72 hours . Under clean conditions , HCoV-OC43 was not detectable on cotton swatches laundered with industrial and domestic wash cycles without temperature and detergent ( ≥4.57-log10-TCID50 reduction ), suggesting that the dilution and agitation of wash cycles are sufficient to remove human coronaviruses from textiles . In the presence of interfering substances ( artificial saliva ), ≤1.78 log10 TCID50 HCoV-OC43 was detected after washing domestically without temperature and detergent , unlike industrial laundering , where the virus was completely removed . However , no infectious HCoV-OC43 was detected when washed domestically with detergent .
As the researchers note , “ Synthetic textiles such as polyester could potentially act as fomites of human coronaviruses , indicating the importance of infection control procedures during handling of contaminated textiles prior to laundering . This study provides novel evidence that human coronaviruses can persist on textiles for up to three days and are readily transferred from polyester textile to other surfaces after 72 hours of incubation . This is of particular importance for the domestic laundering of contaminated textiles such as healthcare uniforms in the UK and U . S ., where there may be a risk of cross-contaminating the domestic environment . It was demonstrated that human coronaviruses are removed from contaminated textiles by typical domestic and commercial wash cycles , even at low temperatures without detergent , indicating that current healthcare laundering policies are likely sufficient in the decontamination of SARS-CoV-2 from textiles .”
Paton , et al . ( 2021 ) acknowledge that the properties of textiles can vary widely depending on the fiber type ( e . g ., synthetic or natural fibers ) and construction of the material ( e . g ., woven versus nonwoven textiles ), which can impact the persistence and transfer efficiency of microorganisms . For example , as the researchers point out , the transfer efficiency of bacteria was greater from woven viscose and polyester than from cotton , silk , and polypropylene .
The researchers observe , “ There does not appear to be any research on the stability of SARS-CoV-2 on textiles during laundering , with a need to determine the efficacy of current laundering processes in removing SARS-CoV-2 from textiles and preventing cross-contamination to other textiles in the wash . Industrial laundering of healthcare and commercial linen is typically conducted under thermal decontamination conditions ( ≥60 degrees C ) or at lower temperatures with the addition of disinfectants . In the U . S .,