Wearing a mask used to be something Australians saw on television or holidays abroad, but now it could save your life or someone else’s.
- Australian experts say consumers need to be careful because masks don’t need to be certified to be sold
- Homemade masks should be produced according to a recommended pattern
- And while N95 masks are the gold standard, there are a few catches when it comes to wearing them
So, it’s important to get it right and it turns out some of the advice we’ve been given could give us a dangerously false sense of security, especially if you don’t know you’re sick.
“The highest amount of infectiousness that you have is in the two days before you develop symptoms,” UNSW biosecurity professor Raina MacIntyre said.
Or you could be asymptomatic and never know you had the coronavirus, but could still endanger others.
So, which mask will best protect you and which will protect the community from unknowing carriers of COVID-19?
Neck fleeces, bandanas and scarves
Initial advice was these were better than nothing and to wear one if you don’t have a mask.
Now it seems they achieve basically nothing, according to new research.
In a study conducted by Duke University in North Carolina, scientists found neck fleeces, bandanas and scarves were virtually useless at containing the spread of the virus.
The study looked at 14 different types of facial coverings, including surgical masks, various cotton varieties, fitted and unfitted N95 masks and something called a neck fleece, often worn to shield the face from wind.
Neck fleeces were found to allow more droplets through than no covering at all because the fabric would disperse large droplets into several smaller ones.
Lidia Morawska is the director of the International Laboratory for Air Quality and Health at Queensland University of Technology.
While noting she had not studied this particular kind of covering, she said: “The American study looks solid, so I agree this is an important finding.”
So with those coverings ruled out, what’s the next best?
Enter, homemade masks
It’s the craft skill Australians never thought they needed.
Homemade masks can be helpful, but there are some tricks you’ll need to know, including that they must contain at least three layers.
Others have done some of the work for you, so it’s safest to use a recognised mask pattern such as the one provided by the Victorian Department of Health.
The ABC’s Dr Norman Swan recommends: “The inner layer ideally should be something like denim, very densely woven cotton”.
Kate Cole is a certified occupational hygienist who specialises in protecting worker health.
She explained the most important part of homemade masks was its fit.
It must fit snugly, providing a seal around your nose and mouth.
“The best one is the one that fits tightest around your face. Ensure your mask includes a nose clip so that the mask fits right onto your nose. If your glasses are fogging up, that is a sign of leakage and that’s bad,” Ms Cole said.
However, even the best homemade masks fall short of the efficacy of surgical masks, according to Ms Cole.
“To be as effective as a surgical mask [for filtration] a homemade mask would need to be up to 12 layers,” she said.
“I’m not suggesting people start making 12-layer masks, but that gives you an idea of the high degree of filtration of a surgical mask versus a homemade mask.”
Store-bought reusable masks
Caveat emptor — the ancient Latin maxim meaning buyer beware — is as relevant today as it was during the plague.
“Purchasing a reusable mask may save you some time in making your own, but it’s difficult to say if they offer any more or less protection than a DIY mask,” Ms Cole said.
That is because there is a lack of regulation.
Australian Stephen Oxley — who is living in the United States — purchased a silicone mask, which uses replaceable paper filters on the inside.
“It’s the most comfortable mask I’ve worn. I wear it all day and forget I’m wearing it,” he said.
While masks with added filtration could provide greater protection, there are no guarantees, Ms Cole said.
“It’s difficult to ascertain whether these types of masks provide more protection to the wearer than a standard three-layer mask,” she said.
“Filters may not be fitted properly or could slide out of place.”
What about those Face Shields that make you look like a welder?
Face shields have been touted as being more effective than masks because they cover not only the nose and mouth, but also the eyes.
Professor MacIntyre does not believe they are a safe option, unless used in conjunction with a surgical face mask.
“The virus is airborne, so a shield will not protect, as air will flow directly up through the gaps under the shield and be breathed in,” she said.
“The US Centers for Disease Control states that face shields are not a suitable alternative to masks.”
Surgical masks take protection up a notch
Surgical masks are made of nonwoven fabric, which provides a much greater barrier than woven fabrics in homemade masks.
Dr Swan explains they are considered safer because “surgical masks are made to a standard which is supposed to guarantee a certain level of droplet [or] aerosol reduction”.
“And that’s been confirmed in comparative studies, where they do perform better than cloth masks.”
Professor Morawska believes they are useful for added protection.
“Surgical masks certainly lower the risk of catching the virus and they do so quite significantly if worn properly,” she said.
While they are a good tool in stopping a carrier from spreading the virus, they may be less effective in protecting the wearer from contracting it.
On its website, the US Food and Drug Administration notes:
“While a surgical mask may be effective in blocking splashes and large-particle droplets, a face mask, by design, does not filter or block very small particles in the air that may be transmitted by coughs, sneezes, or certain medical procedures.
“Surgical masks also do not provide complete protection from germs and other contaminants because of the loose fit between the surface of the mask and your face.”
The gold standard – N95 masks
The Duke University study found the N95 mask — otherwise known as the P2 mask — to be the gold standard.
Professor MacIntyre noted this study confirmed what other research had shown “that N95/P2 are the best respiratory protection”.
An N95 mask is actually a type of respirator and offers protection by filtering out both large and small particles when the wearer inhales.
The 95 in the name indicates the mask is designed to block 95 per cent of very small particles.
N95 or P2 masks are readily available in chemists, hardware stores and even Officeworks, but there are two big catches to purchasing them.
Firstly, if not fitted correctly, they can be useless, and secondly, you may be depriving a health worker of much needed protective equipment.
Ms Cole explained that when used professionally, they needed to be “fit tested” to precisely match a person’s face.
“For members of the public who pop out to the chemist to buy one and put it on, they’re unlikely to work as intended, so are likely to be an expensive waste of money.”
Ramon Shaban, head of infection prevention and disease control for Western Sydney Local Health, warned against members of the public purchasing N95 masks.
“P2 [or] N95 masks are only necessary for use by healthcare workers in specific circumstances, specifically during procedures that generate a lot of aerosols such as placing a tube through the throat to help someone breathe,” he said.
“They should not be purchased or used by members of the public for the sake of protecting against COVID-19.”
Professor Shaban said it was important to understand the role of any mask.
“Remember that face masks are no replacement for physical distancing and good hand hygiene,” he said.
“You should limit your travel and, where possible, avoid any large gatherings.”