Cloth masks can reduce the transmission of viruses like SARS-CoV-2, which causes Covid-19, only if they are washed daily at high temperatures, according to a study.
“Both cloth masks and surgical masks should be considered ‘contaminated’ after use,” said Professor Raina MacIntyre of the University of New South Wales in Australia.
“Unlike surgical masks, which are thrown away after use, cloth masks are reused. While it may be tempting to wear the same mask for several days in a row, or to hand wash or clean it quickly, our research suggests that this increases the risk of contamination, ”Maclintyre said.
The researchers analyzed data from a randomized controlled trial (RCT) they published in 2015.
The latest study, published in the journal BMJ Open, remains the only RCT conducted on the efficacy of cloth masks in preventing viral infections, they said.
The researchers delved into the 2011 data on whether healthcare workers in their study washed their masks daily and, if so, how they washed the masks.
The team found that if the cloth masks were washed in the hospital laundry room, they were as effective as a surgical mask.
Since the study was conducted more than five years ago, the researchers did not conduct tests for SARS-CoV-2.
Instead, they included common respiratory pathogens such as influenza, rhinoviruses, and seasonal coronaviruses in their analysis.
It is based on self-reported washing data and was performed by healthcare workers in high-risk rooms in a healthcare setting.
“While anyone from the general public wearing a cloth mask is unlikely to come into contact with the same number of pathogens as the healthcare worker in a high-risk room, we would still recommend daily washing of cloth masks. in the community, ”Maclntyre said.
According to the analysis, hand washing the masks did not provide adequate protection.
Healthcare workers who washed their masks by hand had twice the risk of infection compared to those who wore hospital clothing, the researchers said.
Most of the people in the RCT washed their masks by hand, and this may be why the cloth masks performed poorly in the original trial, they said.
“WHO recommends machine washing masks in hot water at 60 degrees Celsius and laundry detergent, and the results of our analysis support this recommendation,” Maclntyre said.
“The clear message from this research is that cloth masks work, but once a cloth mask has been worn, it must be properly washed each time before reuse, otherwise it is no longer effective,” Maclntyre said.
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