Why cloth masks may increase your COVID-19 risk

Wearing a cloth mask can backfire if you don’t clean it properly.

Homemade community face masks from cloth as protection against coronavirus pandemic are hanging on a clothesline

Last week Victoria’s face mask regulations changed to ban the use of face shields and make it mandatory for all residents over the age of 12 to wear a fitted face mask when they leave the house.

Masks are also growing in popularity in other states, but while cloth masks are still fine to wear, according to the new Victorian regulations, new research from the University of NSW’s Kirby Institute has raised concerns about how people are using them.

The Kirby Institute analysis says that cloth masks must be washed daily at high temperatures to protect against COVID-19 infection.

“Both cloth masks and surgical masks should be considered ‘contaminated’ after use,” explained Professor Raina MacIntyre, who conducted the study.

“Unlike surgical masks, which are disposed of after use, cloth masks are re-used.

“While it can be tempting to use the same mask for multiple days in a row, or to give it a quick handwash or wipe-over, our research suggests that this increases the risk of contamination.” 

The analysis did not specifically test for SARS-CoV-2 as it relied on unpublished data from a randomised control trial published in 2015, which remains the only trial of its kind into the efficacy of cloth masks in preventing viral infections.

The analysis did, however, look at similar respiratory pathogens such as influenza, rhinoviruses (common cold) and seasonal coronaviruses and was based on self-reported washing data conducted by health workers in high risk wards.

“Given the potential implications for health workers or community members who are using cloth masks during the pandemic, we did a deep dive into the 2011 data on whether the health workers in our study washed their masks daily and, if so, how they washed their masks,” Prof. MacIntyre said.

“We found that if cloth masks were washed in the hospital laundry, they were as effective as a surgical mask.

“While someone from the general public wearing a cloth mask is unlikely to come into contact with the same amount of pathogens as a healthcare worker in a high risk ward, we would still recommend daily washing of cloth masks in the community.

“COVID-19 is a highly infectious virus, and there is still a lot that we don’t know about it, and so it’s important that we take every precaution we can to protect against it and ensure masks are effective,” she said.

According to the analysis, handwashing the masks did not provide adequate protection.

Healthcare workers who self-washed their masks by hand had double the risk of infection compared to those who used the hospital laundry.

The majority of people in the randomised control trial handwashed their masks, and this may be why the cloth masks performed poorly in the original trial.

“The World Health Organization (WHO) recommends machine washing masks with hot water at 60°C and laundry detergent, and the results of our analysis support this recommendation,” said Prof. MacIntyre.

“Washing machines often have a default temperature of 40°C or 60°C, so do check the setting.

“At these very hot temperatures, handwashing is not possible.  

“The clear message from this research is that cloth masks do work – but once a cloth mask has been worn, it needs to be washed properly each time before being worn again, otherwise it stops being effective.”

The original study was conducted in hospital health workers in Vietnam in 2011.

Study participants were randomly assigned to use cloth masks, surgical masks or no masks.

The researchers found that two-layered cotton cloth masks were not as effective as surgical masks in a hospital setting, and that they potentially increased the risk of infection when compared with wearing no mask at all. 

“This has become a flashpoint for the debate around cloth masks between pro and anti-mask groups, both of which have focused on our 2015 study in their arguments – but a more detailed look at the washing data suggests that handwashing made the cloth masks riskier, rather than the cloth mask itself,” Prof. MacIntyre said.

“When we break the data down in this new way, comparing machine washing with handwashing, a machine-washed cloth mask is as effective as a surgical mask.

“There is much research on the design, fabric and construction of masks, but washing is also key for protection.”

Have you been wearing a mask? Do you use disposable surgical masks or cloth masks? How often have you been washing your cloth mask?

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    To make a comment, please register or login
    23rd Oct 2020
    I only have 1 cloth mask, just bought it to donate to charity. Mainly use the disposables, which my work agencies paid for. I throw them out most times.
    23rd Oct 2020
    I have about a dozen cloth masks and wash it after every use. My washing machine has no hot water setting, so, I keep my soiled mask in a zip lock bag. I then put the highest temp water in a plastic bowl and soak it for half hour, rinse it with disposable gloves and wash it thorougly, still in hot water. I hope this is sufficient.
    23rd Oct 2020
    It is essential also to iron your masks on a very hot setting.
    23rd Oct 2020
    Good tip Elizzy
    23rd Oct 2020
    23rd Oct 2020
    I have several cloth masks so I’ve always got a clean one ready. After I’ve worn one I put it into a container of very hot, soapy water to soak and then hand wash it thoroughly, rinse thoroughly, then wash it in anti-bacterial wash for good measure, then rinse again and hang up to dry. Many of us older ladies spent our younger years sanitising nappies, dummies, bottles & sippy cups, etc. so we have a bit of an idea what to do.
    23rd Oct 2020
    I wonder if the high temperatures of ironing a mask negates the need to wash at high temperatures?
    23rd Oct 2020
    Possibly, but better safe than sorry with this virus!
    23rd Oct 2020
    23rd Oct 2020
    Masks are totally useless and are only being mandated as a control device.WAKE UP SHEEPLE
    23rd Oct 2020
    Sorry Steff, but when it come to accepting advice on mask wearing I will defer to the experts, not just in Australia but internationally. I suggest you may be a "sheeple" to unfounded conspiracy theories and deliberate misrepresentation.
    23rd Oct 2020
    Oh, puleeeeze Steff !! Sheeple ?? Hope you have tattooed on your chest Do NOT Use Masks etc whilst undertaking surgery on ME :) If/when you are unfortunate enough to have to undergo surgery. Good luck with that :D
    23rd Oct 2020
    heyyybob, Steff has a point. No, the cloth masks give very little protection from contracting airborne virus particles. That N95 simply means that it will stop maybe 95% of airborne particles. The cloth masks, especially the home made ones, don't even meet this performance criteria.
    The reason that surgery staff wear masks whiles operating is literally to prevent them dribbling into the open work site.
    Sneezing or coughing through a mask simply slows down the expelled draught. It does not stop the droplets beyond getting wet.
    The most effective filter happens to be the nasal passages, so always inhale through your nose.
    The American Physicians Society did an in depth assessment of the effectiveness of masks in infection prevention and basically the only type of mask that actually meets the perception are those that use an electrostaticaly charged laybrynth. And these are not on the market.
    To become infected with the Covid-19 virus there has to be an active carrier in your immediate vicinity. And outside continued contact with a close social situation, over 90% of the population are not at any risk at all. Within Victoria the only areas of concern are restricted to a handful of known locations within the Greater Melbourne area and a couple of others. There is absolutely no justification for people living in the rural areas and country towns to have to wear a mask or any type of face covering.
    23rd Oct 2020
    Eddy, Maybe if you wear a mask correctly it does help but it was laughable watching people on the news and current affairs interviews with ill fitting masks which they kept trying to keep on their faces using their hands(a no-no we were told from the beginning). Every time they spoke the masks moved and there were gaps between the masks and their faces so up would go the hands to push them back into place.
    24th Oct 2020
    Utter nonsense
    23rd Oct 2020
    The arrogance, stupidity and uneducated comments of the "Entitled Generation" dumbfounds me, the comments from the ignorant who believe the the conspiracy theorists and flat earth believers are fodder for the antivax movement as well, they are probably the audiences of stupid shows like SAS Australia that make hero's of drug pushers and fill their pockets with the proceeds of crime, Great roll models for our kids, smuggle drugs and then become a TV hero because of your past, make a quid and make it ok to do drugs.
    Some of these idiots need to be treated with the contempt they deserve.
    Follow the rules and keep safe and do this for the safety of your elderly relatives and your self.
    Wear a bloody mask, Keep it clean or use a disposal one.
    Not hard.
    24th Oct 2020
    This will not be the last virus the entitled generation has to deal with. They will become more frequent and target specific generations. This one was just a test.
    23rd Oct 2020
    I washed my cloth mask in with my general washing but I use cold water so that apparently wasn't much good.
    Will boil my kettle, put on very thick rubber gloves and have a go by hand.
    I am told by a pharmacist that you can use the blue surgical masks for 4 hours before they need to be discarded.
    Because I have asthma it's very hard to breathe with any type of mask and unless I'm going into a supermarket or place where there are a lot of people I don't wear one now.
    23rd Oct 2020
    Teacher, yes, a cold wash does little to sanitise your wash. However if you hang it in direct sunlight and ensure that all surfaces are exposed in due course, this will kill nearly all pathogens (and others) that are clinging to the fabric. (Ultra violet light is the active component. That's why UV sanitisers have appeared on the market for such things as smart phones.)
    The critical temperature is 60 degrees Celsius. For at least one minute. Above is a good idea.
    Otherwise, the virus can be killed with cell disruption and this can be achieved with a solutions of >70% isopropyl alcohol or by using bleach.
    A Ford Police car used in California has a self sterilising function where it closes all windows and warms the interior to around 60 degrees and maintains it for at least 15 minutes. (It is an automatic action, but after warning users it only goes into the sequence when vacated. Better take any chocolates out of the vehicle.)
    23rd Oct 2020
    You are correct Couldabeen. 60C seems to be the minimum and it needs exposed to that heat for several minutes. This article states 65Chttps:

    //www.healthline.com/health/what-temperature-kills-coronavirus :
    23rd Oct 2020
    You could possibly get Covid19 even if you wear a mask. However, your VIRAL LOAD will be reduced and you are unlikely to die or need intensive care. Also the VIRAL LOAD you inflict on others during the few days prior to your symptoms appearing, will be reduced. Masks are mostly to protect OTHERS from YOU and to reduce viral load. Pls excuse the caps, but there are a couple of important concepts to grasp here I think.
    23rd Oct 2020
    Most I have seen are wearing ill fitting masks which they are constantly adjusting by putting their hands up to their faces which we were told from the beginning is dangerous and could cause you to catch the virus from touching surfaces and then your face.
    24th Oct 2020
    I regularly put wet dish cloths in the microwave for 1 minute and they come out so hot they are hard to touch or, if it's sunny, hang them on the line for a few hours. Either way they smell fresh and clean afterwards. Perhaps the same can be done to clean cloth masks.
    24th Oct 2020
    Hi Strummer, I also use the Microwave to sterilise my cloths and sponges
    I would expect it to be adequate for face masks. BEWARE be sure to dampen the mask first or it could set on fire in the microwave oven.
    24th Oct 2020
    Could someone recommend good quality washable masks and where to purchase?
    I've read that KN95 are best at shielding Covid-19. I've been wearing disposable KN95 from Bunnings.
    24th Oct 2020
    Someone is telling porkies? Wash hands with soap for twenty seconds to destroy the virus, but no good for masks unless it is at an elevated temperature. Something does not add up.
    25th Oct 2020
    Exactly. Only last week I read that washing your mask with your normal wash on the cold setting is sufficient. The action of hand washing is the same machine washing, or breaking down the virus wall using detergent.
    25th Oct 2020
    No one wears a mask in WA

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