There’s been much debate around the world about whether the public should be wearing face masks during the coronavirus pandemic.

The US Centers for Disease Control and Prevention (CDC) recommends “wearing cloth face coverings in public settings where other social distancing measures are difficult to maintain”.

In Singapore you’ll be fined if you don’t wear one outside.

In Australia, however, the official advice hasn’t changed — most of us don’t need to wear a face mask.

In a report prepared on Monday, the Australian Government’s Infection Control Expert Group said: “In Australia, the routine use of masks in the community is currently not recommended, while the rate of community transmission of COVID-19 is low.”

But there is still debate here on whether we should.

For instance the ABC’s Dr Norman Swan says wearing masks on public transport is one way of reducing the already low risk of transmission.

“What I’m arguing is that masks would reduce [the risk] even lower, and you could be a bit more relaxed about social distancing on rail trips,” he said on Coronacast last week.

And we’ve still been receiving many questions from you, wanting to know more about how face masks work, and what potential benefits or drawbacks they have.

The bottom line is risk is not a black and white situation and can be quite personal.

We’ve put some of your most common concerns to three experts, so you know what the issues are if you’re going to wear one.

Who is protected when you wear a mask?

The benefits of wearing a mask are two-fold, says epidemiologist Raina MacIntyre, who heads the Kirby Institute’s Biosecurity Program at the University of New South Wales.

“Firstly, it will prevent someone who is infected from emitting virus into the air around them; and secondly, it may well protect people from inhaling contaminated air or being sprayed by sneezes and coughs,” Professor MacIntyre says.

“Every country will need to look at this as societies re-open, larger gatherings occur and people need to use crowded public transport.”

So wearing a mask may well be “an altruistic act that helps prevent you contaminating your environment,” says clinical researcher Meg Jardine of The George Institute for Global Health.

But occupational hygienist Kate Cole cautions there’s limited evidence that face masks in a community setting provide a high grade of protection against coronavirus.

“It’s one level of protection, don’t get me wrong, but it’s not overly effective,” Ms Cole says.

Like many things, wearing a mask is all about reducing risk, Dr Jardine says.

“The more virus fragments you have in your environment, the more likely you are to be affected,” she says.

“If you can just reduce the number of fragments you’re going to reduce risk.”

Don’t waste a good mask

All our experts agree that the best masks should be prioritised for healthcare workers who are operating in the most high risk environments.

“We don’t recommend that members of the community use N95 or P2 masks because we need to keep them for our frontline medical workers,” Ms Cole says.

But it’s more than that, she says. Typically these kinds of masks aren’t used in the way that they’re intended: they’re worn upside down, they’re not fitted well or tight enough, and people aren’t trained or given enough information on how to wear them appropriately.

Even Beyonce has been spotted wearing a mask upside down.

Beyoncé wears a KN95 mask upside down and my heart breaks 💔 https://t.co/H1ZYRJJHbK

— Kate Cole OAM 🇺🇦 (@kate_cole_) May 25, 2020

“It’s kind of wasting that mask and taking it away from the people that need it the most,” Ms Cole says.

Another important thing to be aware of is not to wear a mask with an exhalation valve, because a mask like that filters the air coming into your mask but not the air going out.

“So if you’re sick and you’re wearing a mask with a valve and you sneeze or cough, for example, it’s just coming straight out of the mask unfiltered,” Ms Cole says.

Another issue, that Ms Cole has been documenting on Twitter, is that there’s been a surge in the number of counterfeit masks of this type that have come onto the Australian market.

Dr Jardine has reviewed the evidence for whether cloth masks may prevent transmission of COVID-19.

She says cloth masks are generally not quite as good as surgical masks, but certainly effective, although that effectiveness depends on the number of layers in the mask.

Surgical masks are disposable and should only be worn once. Photo: ABC News / Patrick Rocca

The more layers the more effective the mask.

Professor MacIntyre published the only randomised clinical trial of cloth masks back in 2015, which suggested they were not very good. But she thinks it is possible to design better cloth masks.

“You need multiple layers, a fine weave, high thread count, water-resistant material and good fit around the face,” Professor MacIntyre says.

“They should be washed daily or can become contaminated.”

She says there was more data available for surgical masks which protect better than cloth masks, but are a disposable product and not meant to be re-used.

Learn how to use a mask correctly

Both the CDC and Canadian Government have published advice on the limitations of masks and how best to avoid contaminating yourself as you put them on and take them off.

It’s typically not recommended to use a disposable mask for any longer than a day, Ms Cole says, and you’ll generally find that type of information on the product when you’re buying it.

She also says you should change a disposable mask if you sneeze into it or it gets wet some other way.

Some of you have asked whether it’s possible to reuse disposable masks when you’re only using them for short stints.

Dr Jardine says as soon as you take a mask off you have to treat it as a contaminated object.

The benefit of cloth masks is that you can wash and reuse them. Photo: ABC News / Brendan Esposito

If you don’t want to burn through masks, one idea is to use cloth masks.

Dr Jardine suggests you could wear one mask on the way to work, put that in a sealed container after you arrive, and wearing a new one on the way home.

Then you can wash both of them and reuse them again.

But masks may not be for everyone, she adds.

“As they’re filtering virus it means the airflow is slower so people with breathing difficulties might struggle with those.”

A baby with a face shield. Children under the age of two are not recommended to wear face masks. Photo: AP / Kyodo News

The CDC recommends anyone under the age of two shouldn’t wear a mask.

“Infants, small children just won’t be able to use them. They’re not going to wear them well and there might be other hazards associated with them,” Dr Jardine says.

Unintended consequences of wearing a mask

“Wearing a mask can really give you that false sense of security sometimes, that you are protected from a virus,” Ms Cole says.

It can also cause you to touch your face more and adjust the mask if you’re not used to wearing one, potentially increasing your risk of contamination.

And there is that unintended consequence that people may not follow other advice because they have that false sense of protection, Dr Jardine says.

But Professor MacIntyre rejects the argument that masks will make people take risks and become careless about other measures.

“We have heard these paternalistic kind of arguments against public health interventions before, like ‘HPV vaccination will encourage promiscuity’,” she says.

“I think we need to give people more credit than that and allow them to be empowered to manage their own protection against this pandemic, and trust that people can be educated on correct mask wearing.”

So, should you wear a mask?

“I think in the absence of a formal recommendation [to wear masks], people need to make their own risk judgements,” Professor MacIntyre says.

“If someone works as a bus driver or needs to ride a crowded train every day to work, they may consider it, especially if they are older or have chronic diseases.”

And we need to remember that wearing a mask is “not a silver bullet”, but one way you can minimise your risk, Ms Cole says.

“Physical distancing, staying at home, washing your hands and not touching your face are more effective than simply wearing a mask,” she says.

“Wearing a mask can’t supersede all those other things.”

– ABC